USA Swimming executive director Chuck Wielgus, who led a federation that brought home 156 Olympic medals during his 20 years at the helm, died Sunday. He was 67.

USA Swimming said Wielgus died in Colorado Springs, Colorado, of complications from colon cancer. The cancer was first diagnosed in 2006 and Wielgus underwent regular chemotherapy while leading USA Swimming to record growth. He was due to retire in August.

He had announced his planned retirement in early January on the same day he learned he’d been approved to use a new cancer drug that’s in clinical trial.

“Chuck fought a long and hard battle with amazing grace and optimism, and will be missed,” U.S. Olympic Committee CEO Scott Blackmun said.

Wielgus was the longest-tenured leader among U.S. Olympic organizations. The 156 medals represent about one-third of America’s overall total from the last five Olympics.

advertisement | advertise on newsday

During his two decades, USA Swimming’s revenue increased by about 600 percent, and its four-year, Olympic-cycle budget grew from $35 million to nearly $160 million. Membership more than doubled, to 400,000-plus, and Wielgus helped turn swimming’s Olympic trials into a showcase event. The 2016 trials sold out more than 200,000 tickets.

Wielgus came under fire in recent years for his handling of numerous sexual-abuse cases against the organization, with some calling for his resignation. After saying he had done nothing wrong in a defiant TV interview in 2010, he apologized four years later, writing in a blog: “I wish my eyes had been more open to the individual stories of the horrors of sexual abuse. I wish I had known more so perhaps I could have done more.”

The national governing body said current assistant executive director Mike Unger will serve as interim executive director. Unger has taken an active role in helping run the organization while Wielgus was dealing with his illness in recent years.

Wielgus’ vision to promote swimming to wider audiences resulted in securing year-round television coverage of major events, including the Pro Swim Series, national and world championships, U.S. Olympic trials, Pan Pacific championships and Duel in the Pool.

During his tenure, the annual Golden Goggle Awards and fundraiser began to recognize that year’s accomplishments.

@NewsdaySports

Wielgus helped create the USA Swimming Foundation, which provides financial support for national team athletes and helps to save lives through swim lessons with the Make a Splash initiative. He served as chief executive officer when it began in 2004.