24 Hour Fitness partnered with NBC to develop a reality show, The Biggest Loser, which features 12 to 22 overweight contestants competing to lose weight over several million dollars.

Besides the United States, it had centers in Singapore and Hong Kong, Beijing and Shanghai in China) through its wholly owned subsidiary California Fitness (CalFit).

[12] In August 2012, the owner of 24 Hour Fitness put the 416 location gym chain on the auction block with a price tag reported to have been close to $2 billion.

[14][15] In May 2014, Forstmann Little & Co. reportedly sold 24 Hour Fitness Worldwide Inc. for $1.85 billion to an investment group led by AEA Investors LP and the Ontario Teachers' Pension Plan.

[20] As of 2023, 24 Hour Fitness operates nearly 280 clubs in eleven states: California, Colorado, Florida, Hawaii, Nevada, New Jersey, New York, Oregon, Texas, Washington and Virginia, with more than 7,500 employees.

In 2010, the court found that 24 Hour Fitness did not act in good faith after denying members who purchased an "All Club" membership access to rebranded locations without charging additional fees not disclosed in the original contract.

This lawsuit was brought in the State of California pursuant to allegations that 24 Hour Fitness discriminated based on race and gender in their promotion practices.