Steve Barsh spends his workweeks mentoring startup founders, consulting with artificial intelligence experts and advising organizations like SeatGeek and NASA.

For one to two hours per day, the full-time startup investor also runs his side hustle, a property management company called Parker Chase Properties that manages short-term rentals across five luxury condo units in Park City, Utah, and Deer Valley, Utah.

The side hustle started 26 years ago when Barsh sold a software startup he co-founded called SECA, and together with his wife Amber Salzman, bought a $820,000 three-bedroom condo in Park City. The Philadelphia-based couple used the condo for vacations and rented it out through a property manager for the rest of each year — until Barsh, annoyed at how much he had to pay the property manager, decided to handle bookings himself, he says.

Salzman and Barsh now own four of the five condos managed by Parker Chase, which brought in $1.27 million in revenue — roughly $105,000 per month, on average — on Airbnb, VRBO and travel software platform Hospitable last year, according to documents reviewed by CNBC Make It. (Barsh is an investor in Hospitable, according to the company.)

Barsh pockets 40% to 50% of those bookings as profit, he estimates. He essentially runs the side hustle solo, contracting only with a housekeeping company and, when he's traveling, a backup property management company, he says.

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Now a full-time Park City resident, Barsh "refined" his guests' experience over time, he says. He pictured travelers wanting to kick back in leather chairs, drink cold beers from a mini fridge and watch ESPN on a wall-to-wall flat-screen TV — when they weren't skiing on nearby slopes — and spent to make such luxuries possible, anticipating that the investment would pay off later.

He collects feedback from guests constantly, and refuses to cut corners, he adds. Most of the time, Parker Chase's positive reviews come from small details, like lint rollers in the laundry room. Once, one of Parker Chase's regulars told Barsh that she desperately needed a rice cooker, he says. He stopped at Costco and texted her a photo of one on the shelf.

"She was like, 'Not a crappy American rice maker, a Chinese rice maker,' and sent me a link to a $390 version," Barsh says. "It was a no-brainer for me."

Barsh's property management side hustle is decidedly upscale — it's hard to create a luxury experience for guests without spending money first, including the roughly $10 million he and Salzman spent to purchase their four condos, he says. (The funds came from a $4.3 million sale of their initial condo, and money that Salzman, a longtime biotechnology executive, made in a corporate acquisition, Barsh notes.)

Correspondingly, a night at a Parker Chase property is pricier than the average vacation rental: The company's current availability for March shows a median price of $3,390 per night. The average daily rate for an Airbnb or VRBO listing in Park City is $761, according to an estimate by short-term rental analytics company AirDNA.com.

Barsh pockets more money from Parker Chase than the combined salaries of the average property manager and real estate investor in the U.S., based on data from job search platform ZipRecruiter. He also uses his side hustle to teach his two children how to invest in appreciating assets, and he genuinely enjoys the hospitality aspect of running the business himself, he says.

"Four Seasons, when they hire people, know that they can teach people how to work a front desk, open a front door or clean a room, but they look for people with that hospitality instinct," says Barsh. "I don't know what it is in me, but I really enjoy hospitality. I really enjoy when people tell me they've had an amazing experience. It just makes me feel good."

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