How the 43-year-old founder of [solidcore] made $100 million as her competitors went bankrupt

“I know how to operate in a crisis,” Mahlum, the 43-year-old founder and former CEO told Fortune. She characterized her war, as it were, as the pandemic, which sent many similar fitness chains—like Flywheel Sports—swiftly into bankruptcy. “I don’t care what it was. No one was going to take from me what me and the team had built. I was going to do whatever it took.”

Mahlum, who sports spiky blonde hair and a serious demeanor, has maintained her toughness for decades. She’s a startup advisor, an investor, and has run more than 10 marathons. Her first love, prior to [solidcore] was Back on My Feet, a nonprofit geared at uplifting and empowering homeless populations, starting with weekly runs. 

That hard exterior has also raised accusations of abuse. In 2020, per a BuzzFeed News report, Mahlum faced allegations from more than two dozen [solidcore] employees of harassment and fostering a hostile work environment based on fear and shame. A petition calling for her ouster garnered over 400 signatures. 

Mahlum remained CEO until April 2021, when she pivoted to executive chairwoman. Last year, Mahlum divested her financial interest and left the company she founded. She notes to Fortune that the anonymous complaints of her management style did not affect her company’s bottom line or result in any change to the company’s trajectory.

Mahlum criticized the Buzzfeed reporting as one of a series of “female take-down articles using anonymous sources,”  adding,  “If that article had any truth, I wouldn’t have raised $50M five months later and I wouldn’t have continued to work there for two more years.” She did not comment on the online petition with hundreds of signatures.

“When you continue to rise as a woman, there will always be people waiting to take a shot at you,” Mahlum said. In an interview with Fortune, she charted her path from North Dakota waitress to entrepreneur to self-made multimillionaire. 

The following conversation is lightly edited and condensed, and includes descriptions of disordered eating. 

Where are you from? 

I grew up in Bismarck, North Dakota. I had a pretty normal childhood. Both my parents worked—my dad sold insurance and my mom was a teacher. I played a ton of sports in North Dakota, and had a super safe upbringing. We didn’t lock our doors, and we left our keys in our car. I thought everybody grew up the same way I did, with a bike and a big yard. Pretty normal childhood until I was 16 or so.

What was life like financially for you growing up?

We didn’t have a lot. My mom was a teacher, so she didn’t make a ton of money. And my dad’s never really been good with money. He’s faced a few addictions in his life—drugs and alcohol—when I was really little. And then my dad unfortunately had a gambling addiction. So money was always a very tenuous thing between my mom and dad. My dad ended up gambling away a lot of what little [money] we had when I was a teenager. 

How did finding out that your dad gambled most of his money away affect you?

I remember that day really clearly. It was the summer before my senior year of high school. My dad came home, and I could tell something was wrong. He asked me, my brother, and my sister to leave for a while so he could talk to our mom. We left, and I was the first one to come back. That’s when my dad shared that he had been gambling and got himself into a good amount of trouble. He owed about $50,000, which we didn’t have, and he didn’t have. 

I don’t think I understood the magnitude, at that time, as a 16-year-old. But my mom asked my dad to leave that day. And for a 16-year-old kid who thought her dad hung the moon, it had a massive impact on me. I took my resentment out on my mom. In that moment, I decided I never wanted money to cause conflict in my life. I never wanted it to be a problem for me. I wanted to have enough of it. I just never wanted to find myself in that situation again.

At what age did you get your first job?

I started working when I was 16 years old at a restaurant called Perkins. I started off as a hostess and then went on to be a server. I think it was a very formative experience. 

Did you start your first job after you found out about your dad’s gambling?

I think I was already working. In our household, we were always encouraged to work. My parents kind of demanded that we get a job when we were 16 years old. My brother, sister and I all worked at Perkins restaurant. 

I worked at Perkins all the way through high school until I went to college, and then I worked at Perkins there. Then I got a job at a more upscale restaurant that served alcohol and nicer food.

 Where did you go to college? 

St. Cloud State University in Minnesota. I majored in political science and communications. I graduated in three years because I was in such a hurry to be an adult and have a job,make money,get married, and have kids.

Were you interested in entrepreneurship in college?

I remember being out with my girlfriends in high school, and we were always talking in the car, and they were making fun of me for something. And I remember getting out of this car, slamming the door—this is in the middle of winter in North Dakota—and saying to them, “I’m going to be somebody someday.” My friends always remind me of that when I go back there now, but I always knew I was really driven. I didn’t know what I wanted to do, but I wanted to do something big and impactful for my own purpose in life.

Were you always passionate about fitness? 

Yeah, I got into fitness at a young age, probably for the wrong reasons—some 12-year-old kid called me fat. That stayed with me for many of my teenage years. Like a lot of women out there, I had my fair share of body issues. I went through periods of my life where I was throwing up my food. Working out for me, in my teenage years and young 20s, was always about body image, and I had a frankly unhealthy relationship with working out and with food. It was always, how can this make me look skinny? How can this make me look better? It took a while for me to really build a healthy relationship with food and exercise.

What was your relationship with money like?

I had a very small-minded view of money when I was in my mid-20s. I still remember a phone call when I was 24, and I wasn’t making a lot of money, and I wasn’t really good with my money. I wasn’t saving. I was just spending it. And I remember calling my mom—I was over marriage and kids at this point—and I asked her if she could front me the money for my wedding since I wasn’t planning to get married.

My mom has a scarcity mindset about money. Her view on money is: you save it, you never spend it. So I think she was a little disappointed in me for asking for it. But she did give it to me, because she gave my brother and sister $5,000 for their weddings. She just reminded me that, okay, if you want it now, you’re not gonna get it later. And I took it.

I spent that $5,000 on everyday expenses. It’s not like I did anything wise or smart with it. I just didn’t have the wherewithal, and I didn’t really care about anything else besides how my body looked and my food addiction. 

I was in credit card debt. It sounds so silly, but I wasn’t buying things. I was mainly buying food and then throwing it up, not realizing how much I was spending on ice cream and candy. When you’re doing that three to four nights a week, it adds up, and when you’re only making $50,000 or $60,000 a year, I was definitely not good with money, financially and literally feeding my food addiction.

What was your turning point?

I still had body issues all the way up to, frankly, the beginning of [solidcore]. When I was 24, 25, and 26, my bulimia was really bad. For those of you who understand this, your addiction takes priority over everything. You cancel plans, you lie to friends, you lie to family—and I was definitely doing all of that. 

I remember looking in the mirror after a night of throwing up my food and shaming myself. I was like, you’re so stupid. I can’t believe you do this. This is so horrible for you, why can’t you just stop. And then two days would go by and I was back in the same situation. It was just so hard. It was so much a part of my identity, I just couldn’t get out of it. And then frankly, when I had this idea to start a running club for the homeless, which turned into a nonprofit, I stopped being sick. I think I stopped being sick because I finally started caring enough about other people, and I knew I couldn’t be sick and help these people at the same time. 

Can you talk a little bit more about the sporting club that you started and why you decided to do it? 

When I was 26 or 27, I was completely lost in my life. I wanted purpose, and some sort of reason why I was here.And I was running every day at 5:30 in the morning, and there was this homeless shelter that I ran by on every morning run.

One morning, these guys waved at me, and I’m from North Dakota: if you wave at me, I’m gonna wave back at you. And we just started building this relationship. It was like a light bulb where I thought, Oh, my God, I’m going to start a running club for these guys. I knew the power of running. I mean, I felt so alive, and I felt so in control of my life when I was running. And I didn’t think it mattered if you were white, black, rich, poor, homeless, or some 16 year old messed up kid like I was—running could really be beneficial. So I called up the homeless shelter. It took some convincing, but that idea really changed the trajectory of my life.

It took a lot of learning, but I built that into a national nonprofit, and ran it for six-and-a-half years with a $6.5 million annual budget. It still operates today in about 15 different cities with a budget, I think, of around $8 million. It’s still called Back on My Feet.

How did you come up with the idea of [solidcore]?

Six years into Back on My Feet, I started to get this feeling that it was time to do something else. And I was upset. I was like, I took this massive risk, my life is so fulfilling, I get to help all these people, where’s this coming from? I tried to brush it off, but it just kept coming back up. 

So I was in LA, getting ready to launch Back on my Feet in LA, and I walked by this studio. It was like a pilates-esque studio and was very pink. I thought it was very LA and very cute. I was working out a ton at this point. I’d done marathons, triathlons, you name it. And I was like, okay, I’ll go take this class. And I got my butt kicked. I couldn’t believe how hard it was. It didn’t make sense to me that it was so hard. And the next day I was sore in all of the places that, as a woman, I was trying to target. My core, my obliques, my inner thighs. 

I found a similar workout back in New York called SLT. I took a class and Amanda, the founder of SLT, was there one day, and I was just like, this is an incredible business. I started doing the math on how many people were in the class, how many machines there were, and I started to ask some questions. She was very forthcoming and very willing to talk to me and tell me how her business worked. I was like, this is what I’m going to do next. 

I didn’t think that many people knew that you could work out this way. And the results? I was seeing the strength I was developing. What I’m best at is building branded experiences. And I thought I could take everything I had learned at Back on my Feet, and put that into this new type of workout and build a really incredible brand. 

What were the first initial steps to actually getting [solidcore] once you figured it out that that’s what you wanted? 

I moved back to DC. At that point, I had spent some time there, and I knew it was a fluent market and I felt it would be the perfect place to launch the first [solidcore] studio. So I went back there. I had saved. I got a little bit better with money during Back on my Feet, and I had saved $175,000 from bonuses and salaries from speaking engagements. The reason I saved $175,000 was because I think I knew at some point, deep down, I was going to want to do something else, and I wanted to be able to have enough money to back myself. 

That’s pretty much all it took—like 95% of that $175,000 to get this first studio open. For anybody watching this, who’s had an idea they’ve talked themselves out of it, because they’ve never done it before: any entrepreneur you’re going to find didn’t do it before. I had never. I didn’t know anything about commercial real estate. I didn’t know anything about running a for-profit business, I didn’t know anything about building out a studio. I had to learn all of those things, but I still felt so confident in my ability to build the brand and focus on the community, and I trusted that I would be able to figure those things out. 

So I left Back on my Feet in August of 2013, and had my first [solidcore] Studio open that November.

How old were you when you opened the first [solidcore]?

33.

How were you so comfortable taking the risk of investing your entire life’s savings into [solidcore]?

That’s a good question, I get asked that a lot. I think I was so comfortable because I had been taking risks my whole life. I was the first one in my family to move away to a college where I didn’t know anybody. And then I moved to DC all by myself. I rented a room with three roommates I’d never met. I cut my hair off. These are little everyday examples of my taking risks. It didn’t feel so scary when I was going to bet on myself, because I had all of those examples and data of it working out, it was okay. I’m not going to grow if I don’t take risks. 

Everyday risks you take, like going to dinner by yourself or cutting your hair, those do add up. They give you the competence to know that you can start your own business, and the ability to trust that you’re going to figure it out. 

How long did it take you to bring back that $175,000 after starting?

Fortunately, my predictions about [solidcore] came true. We were very busy from day one. I got pretty lucky with the timing. In 2013, there was really no boutique fitness in DC. There was no SoulCycle, there was no orange theory, there was no flywheel, there was no Barre, there was nothing. So when I showed up with this new type of workout, people were really curious. I was able to get some good press, and people came right away. 

Fortunately, people started telling their friends. One thing I have learned about [solidcore] is that our biggest marketing tool was the fact that everybody had to go tell everyone they knew how sore they were. They wanted to be the ones to tell their friends that they had to go try this because it gives them good social cred in their circle. So we were really busy from the start and profitable from month one.

When did you actually make your first million dollars that you were able to call yours? 

I made my first million dollars in 2013, the first year of [solidcore], which is pretty incredible. I know that’s not normal, the money I was putting back into the company. But I was able to because I was 100% owner in the business, and I could take out enough distributions to have a million dollars in my bank account. Then I bought my first house.

First off, I saved $175,000 over the course of six years, knowing I wanted to back myself at some point. And once I had the idea for [solidcore], I was all in. So I put all my chips on the table and opened my first studio. And because I had everything riding on that, I was not going to let this thing fail. I did everything I possibly could to make sure that we opened with as many people interested in knowing about the studio to make sure it had the best chances of being successful. And fortunately, people had the same reaction to [solidcore] that I did, which was, oh my god, what is this? This is amazing. Where’s this been? And so we were just flooded with business from pretty much opening our doors. And then I opened the studio to studio three, studio four. And within that first year, I made my first million dollars.

When you were able to finally pay yourself a large amount of money, what did you spend it on? 

I bought a house and bought my [childhood] house from my dad. Those were the two big purchases I made with the money I had in those early stages. I started to get smart with money. I started to educate myself and learn and talk to people. I have an excellent accountant. I started reading books, and I knew that if I could continue to put the money I was making from [solidcore] into appreciating assets, that it would all just continue to multiply. 

How did you feel when you finally had a million dollars and could buy your house? 

One of the greatest pieces of advice I have heard about money is that money follows, it doesn’t lead. That really stuck with me, because what I was focused on was not really making money. There’s nothing wrong with making money, but what I was focused on was building an incredible company. I had the time of my life building this business—I loved every second of it—and I put in time and energy like you wouldn’t believe. When you do that, as an entrepreneur, money is a reward. It means I’m doing a good job, that what I’m doing is quality, it’s valuable, people are coming back. 

I’ve been very deliberate about my relationship with money over the years, because there was a time when I thought $1,000 was a lot of money. If I continued to think $1,000 was a lot of money, my mindset around money was going to be small. When I was making a million dollars, I told myself that this is just the start, and you need to get really comfortable with having money. You can do a lot of great things with this money. You can support your family, you can make an impact, you can help people. You need to step into this and make sure you’re making the right decision. So I think I just continued to mentally prepare myself for the kind of wealth that I have today. 

What is the most expensive thing you’ve ever purchased for yourself? 

The most expensive thing I ever bought was a house in Miami that I moved into two months ago. It was $12 million.

Do you know your current net worth?

It’s close to $100 million.