It was a moment of history and heart at the inaugural Katie Ledecky Invitational. On the final day of the meet, Katie Ledecky touched the wall in the 1650‑yard freestyle at 14:59.62. In doing so, she shattered her own U.S. Open and American record and became the first woman ever to break 15 minutes in the event. Cheers erupted from the stands, but one voice stood out the most: her brother, who had been counting every lap with her from the sidelines.

Right after she finished, Michael, her older brother, shared the video on Instagram.  It was Katie touching the wall, and soon after, the camera caught Michael’s expression, who was standing across the pool, smiling and clapping. Instantly, Katie reshared the video on Instagram with the caption: “Thanks for counting… just like old times.” Later, Katie also shared a photographer’s post of Michael cheering for Katie.

Katie captioned it: “Thanks to all the swimmers who offered to count.” Even fans got emotional. One person on X wrote: “Katie’s brother counted for her… I’m actually in tears.” Seeing her sister succeed clearly made Michael’s heart swell, especially since it was his love of swimming that first inspired her. As Katie Ledecky once shared, when she was six and Michael was nine, she followed him to a summer league swim team. They loved it so much that they joined a year-round team.

“I swam with my brother all the time and always followed him to the pool. I wanted to be in the same group as him for everything,” Katie Ledecky said. “I just always enjoyed swimming with him, and I think that’s how I really found my love of the sport. I think if I didn’t have my brother swimming with me, I don’t know if I would have loved it as much as I did and still do.” However, Michael has always been her biggest supporter.

Sure, he also loved swimming until college. But after college, Michael moved into business and strategic roles. In 2016, writing for the Harvard Crimson, he said about Katie: “She has nerves of steel and works harder than anyone I know. I am her number one fan.” Today, Michael is the Founder and Managing Partner of Clay Path Partners, a search fund focused on building enduring businesses.

But backing Katie Ledecky wasn’t always easy. Her sibling rivalry shifted when she started dominating in the pool.

The race that tested Katie Ledecky and Michael’s bond

In the memoir Just Add Water: My Swimming Life, Katie Ledecky remembers how Michael first celebrated her wins without holding them up against his. But also as she started bettering his times, he struggled with frustration.

Katie gave readers a peek into Michael’s thoughts as she shared, “Each event burdened me with new layers of exasperation that gradually crushed me. By the final day of the meet, only a brittle shell of a swimmer remained in my spot on the pool deck. How Katie managed to surpass me in my primary sport baffled me… Why can’t I beat my younger sister?”  Their competitive tension came to a head during a 200-meter freestyle race.

Michael desperately tried to prove his superiority but lost to Katie. Katie Ledecky recalls, “When I beat him, he ripped his goggles off, breaking them in half. Something that embarrassed him almost as soon as he’d done it. He was freaking out because the race showed his lack of personal progress.”

With time, Michael figured out how to reconcile his competitive feelings. Katie shared, “He felt a good deal better and proud when he noticed several months later that my times were faster than everybody else’s at his all-boys high school.” This gave him relief, both in her talent and secondarily in his own. He could no longer keep up, so he made the switch to sprint freestyle from long-distance races where Katie was dominant.

This enabled him to swim more competitively in a close range with his sister and have fun swimming with her. As they grew, their rivalry softened into pride. Their pivotal moment in the spotlight came in 2012, London Olympics, when Michael witnessed Katie Ledecky capture her first Olympic gold. Since then, he has been the biggest cheerleader of Katie Ledecky, and it’s only because of him that she was able to have a glorious Olympic career, winning nine gold medals.