Meet Katie Grimes, the Olympic Swimmer Katie Ledecky Has Dubbed the Future of Their Sport

Katie Grimes wasn't going to let one disappointing swim sink her chances of going to her first Olympics.

Or her second.

"I'm just a stubborn person by nature," the 18-year-old athlete, who will be competing in both the pool and open water at the 2024 Olympics in Paris, told E! News in an exclusive interview.

Recalling her turnaround at the U.S. Olympic trials in 2021 after her seconds-too-slow finish in the 400-meter individual medley, she said, "I was really upset, but I was not going to let that be my trip. I was so excited for this goal of mine, and I just wasn't going to let it slip away like that."

So after coming up short in the race she was most confident about, she flipped the script and ended up finishing second in the 800-meter freestyle final—enough to punch her ticket to Tokyo at only 15 years old, making Grimes the youngest member of the entire U.S. Olympic team that year.

The winner of that race, meanwhile, had some encouraging words for the youngster who joined her on the podium.

"I told her after her mile the other day when she got third, I said, 'You're the future,'" Katie Ledecky, who made her Olympics debut at 15 and went on to become the most decorated female swimmer ever, told NBC Sports when they finished one-two. "And I told her after that [final], like, she's the now."

Grimes finished just shy of the 800M freestyle podium in Tokyo—Ledecky won her third straight gold medal in the event—but the teen had posters of Ledecky on her bedroom wall growing up in Las Vegas, so getting that endorsement from her idol was kind of a big deal.

"That was pretty crazy," she said, reflecting on the compliment she could still barely wrap her head around, even though the pair are now known as "Katie Squared" on the circuit. "She and Michael Phelps were the It-swimmers, so I always looked up to her. To hear her say that was definitely shocking at first—I don't think I even comprehended it—but it was cool, for sure."

While Grimes ended up dropping the 800m from her stacked program and finished last in the 200-meter freestyle final at the 2024 Olympic Trials in June, her chances of being "the now" in Paris improved with her win in the 400-meter IM and her second-place finish—to, who else, Ledecky—in the 1,500-meter freestyle. 

Grimes credited all the work she's been doing, in the pool and out, for feeling so resilient, physically and mentally.

"I get the saying, 'work smarter, not harder,' but I feel like we do both really well," said the 5-foot-10 athlete, who's coached by Sandpipers of Nevada CEO Ron Aitken. "That's helped propel me and has given me confidence for this coming summer, because we have literally put in so much work—so many meters—that I know I can do anything. I have full confidence in my body and in my mind."

She's also simply stronger and faster than she was three years ago. "I can lift heavier weights," Grimes said, "and have been able to take more on aerobically."

Part of working out smarter, meanwhile, is "being aware of what you're putting in your body," she noted, "and making sure you're getting the right vitamins and nutrients." When her electrolytes need replenishing, she loves a grape-flavored Powerade and is proudly a face of the sports beverage brand's "It Takes More" campaign, celebrating the type of all-in dedication that Grimes embodies.

"During practice, fuel is number one," Grimes said. But it's also about "putting in that extra effort when nobody's watching, the extra credit that you do outside the pool."

Speaking of extra credit, when she spoke to E! in June with the Olympic swimming trials still ahead, Grimes was headed to Paris no matter what: She earned bronze last July in the 10-kilometer open water event to become the first American to make the 2024 U.S. Olympics team in any sport.

Of course her intent is always to win—and you don't just dive into Hakata Bay in Fukuoka, Japan, and swim 6.2 miles without knowing exactly what you're doing. But placing was admittedly "a little bit unexpected" for Grimes.

"I had never placed top-three in an international 10k before," she explained. "But I just had this feeling before the race, I might be able to do this."

Still, when she clocked her Olympics-worthy time of two hours, two minutes and 43.2 seconds, "I was just so surprised when I saw that result, like, 'Holy cow, I can't believe it!' But I'm totally stoked, super excited."

So, back into the suitcase went her must-pack item: Wilson, the stuffed bear she's had forever and takes on all her travels. "This sounds really ridiculous, 'cause I'm literally 18," she said, quipping, "but if I don't have it in the hotel room, I don't hit my REM."

Though it's her second Olympics, in many ways it'll be a first-time-for-almost-everything adventure, including the opening and closing ceremonies, which she and many other other athletes skipped three years ago.

In Tokyo, "the stands were empty, everything was empty," Grimes recalled. "Not even my parents were able to watch—nobody's were."

And having her family with her in Paris will mean the world. "Explaining it to them or showing pictures is one thing," Grimes said, "but them being there to be a part of it will be awesome. They work just as hard as I work, so I'm excited that they get to be a recipient of those rewards as well."

Not that Christian and Shari Grimes are matching their daughter lap for lap, but they have been her biggest champions since she followed big brothers Sawyer and Carter into the pool and started training with Sandpipers of Nevada—where the coaches recognized early on that she had Olympics-caliber potential.

"I wouldn't say it was inevitable," Grimes, who's the youngest of seven, said of her trajectory from watching her siblings compete to wading in herself. "It wasn't this thing where my parents were like, 'All the kids are swimming.'"

She was 3 when Carter—a gymnast before he hit a growth spurt that didn't stop until he was 6-foot-4—joined Sandpipers, followed by Sawyer. "I watched them have fun, I'd go to their swim meets and cheer for them," she said. "And then of course I wanted to do everything they do, so I took lessons—and it turned out pretty good."

And at this year's Olympic Trials, she got the 400m IM result she'd been hoping for.

But even before she punched her ticket to the pool at Paris La Défense Arena, she'd had a promising spring, winning the 400m IM, plus three other events, at the Fran Crippen Swim Meet of Champions in April. Then she won the women's 10k at the 2024 Open Water National & Junior National Championships in May with a time of 1:58:18, four minutes faster than the time that got her into the Olympics.

During those marathon swims, "I'm constantly calculating, constantly going over strategy," Grimes shared. Practice sessions can be "a little more meditative, but it's still grinding, still taking a lot of mental effort to be 100 percent in the moment."

"Because if you're not in the moment," she added, "then you could be wasting movement. It's definitely important to be focused on what you're doing while you're doing it, and try not to drift off too much."

Even when she's not swimming, her mind is admittedly never too far from the water. So Grimes has to purposefully give her brain a rest when she can, whether she's watching Shark Tank in her hotel room during tournaments, chilling with her family at home in Vegas or taking her 1969 Corvette Stingray out for a drive, the gears of the classic car requiring her full attention.

When she needs to do the opposite and lock in, it's Dua Lipa's aptly named album Radical Optimism that's been getting Grimes pumped for the pool lately.

"Lots of bangers on that one," she said, and "everybody needs a little optimism heading into the summer."

Especially if they're swimming against Grimes.

Check out the best candid moments from the 2024 Olympics so far:

Surger John John Florence of Team USA got jiggy with it as he and his teammates celebrated the Opening Ceremony in French Polynesia.

Olympic gold medalist Nadia Comaneci shared an excited moment with French Tennis player Amelie Mauresmo during the torch ceremony.

Team Japan didn't let the downpour soak their spirits as they lived it up during the Opening Ceremony.

Team New Zealand was clearly in a celebratory mood as they sailed down the Seine during the Opening Ceremony.

Surger Saffi Vette of Team New Zealand made sure to pour carefully as she partook in the sand ceremony in French Polynesia.

Team USA landed an incredible moment during the 2024 Opening Ceremony as they marked the start of the games in Paris.

Recently appointed official Hype Man for USA Water Polo Women’s and Men’s National Teams Flavor Flav looked the part while attending the Games in full water polo garb. 

Snoop Dogg greets the crowds as he holds the torch ahead of the Opening Ceremony. 

Malaysia's Johnathan Guanjie Wong is ready for a bullseye as he practices shooting. 

Sweden's Vilma Bobeck and Rebecca Netzle wave a quick hello as they practice for women's skiff racing. 

Spain's King Felipe VI and Queen Letizia attempt to stay dry as they take in the Parade of Nations on Paris' River Seine. 

USA's Caroline Marks gets in some training time in Tahiti where the 2024 surfing events are taking place.  

Sibel Altinkaya of Turkey has her eyes on the prize—and the ball—ahead of her table tennis games. 

The U.S. women's Olympic tennis team—featuring Emma Navarro, Danielle Collins, Jessica Pegula, Desirae Krawczyk, Coco Gauff—ace a quick selfie. 

USA's Jagger Eaton prepares for his second Olympics after earning a bronze medal at the 2020 Tokyo Games. 

Henry Hutchinson of Australia scores a try in his game against Samoa.

Simone Biles practices on a balance beam while training for the 2024 Olympics.

The French and American men's rugby teams fight over possession. 

Frederick Richard hits the gymnastics floor to train on the parallel bars.

Spain's Carlos Alcaraz takes everything in as he prepares for his Olympic debut. 

Norwegian players Christian Sorum and Anders Mol join Australian players Zachery Schubert and Thomas Hodges on the sand for a volleyball practice session.