Marc Grondahl Remembered as Industry Trailblazer, Role Model & Friend

The co-founder of Planet Fitness, Grondahl leaves behind an impressive legacy he built alongside his brother, Michael

Marc Grondahl, the co-founder of gym giant Planet Fitness alongside his brother Michael, died suddenly last month at the age of 59.

Grondahl was one of the most well-known figures in the industry, creating a legacy brand that revolutionized big-box gyms and affordable, accessible fitness across the globe.

In 1992, when he and his brother acquired a struggling Gold’s Gym franchise in Dover, New Hampshire, the two identified a gap in the market thanks to their business backgrounds — they saw that traditional clubs weren’t successfully capturing mainstream consumers. 

They then set out to create a space that juxtaposed the intimidating nature of bodybuilding atmospheres, branding itself as the trademark “judgement-free zone,” leading to Planet Fitness and its explosion into one of the world’s largest fitness franchises.

Grondahl served as CFO and chairman of the board at Planet Fitness, helping the company to transition to a franchise model in 2003 that has fueled its success.

“I started at Planet Fitness in 1993, at 20 years old, one year after Marc and his older brother Michael co-founded the business,” former Planet Fitness CEO Chris Rondeau shared on LinkedIn in tribute. “For the next 20 years we worked side by side, building Planet Fitness into the first real disruptor in the industry, pioneering the $10 membership so first-timers could feel comfortable and finally afford access to fitness.”

“Marc helped shape the CEO I would later become, and the two of them gave me the opportunity of a lifetime: the chance to work alongside them and earn sweat equity when we began franchising in 2003, ten years into building the model together,” Rondeau wrote. “He was the kindest, most genuine man I’ve ever met. Pure of heart, through and through.”

Grondahl grew up in Moosup, Connecticut, living an active lifestyle centered around sports like football, basketball, baseball and golf. His business ventures extended beyond the fitness industry, helping to build the New Hampshire-based storage facility Bluebird Self Storage.

Grondahl is predeceased by his parents, Brenda and Eric, and survived by his older brother Michael and his wife Lisa, and his younger sister Lisa and her husband Hal, as well as an extensive loving family of uncles, aunts, cousins, nieces and nephews. He also leaves behind his cat, Tiffany.

Grondahl’s family is planning a celebration of his life to be held on August 30th at Wentworth By the Sea in New Castle, New Hampshire, from 2 to 6 p.m.