"It feels like gold that I'm after her", she said of Ledecky.
The last swimmer to sweep the three events was the U.S.'s Debbie Meyer at the 1968 Mexico Games.
Maya DiRado of the United States won the women's 200 backstroke, reeling in Hungary's Katinka Hosszu in the closing meters to deny her a fourth gold medal.
"It's surreal, kind of absurd and, you know, when I touched, turned around and saw the one next to my name, I kind of smiled and laughed", Ervin said.
"I have got great googles so I could see around me".
Four years ago, Ledecky seemingly came out of nowhere to capture gold as a 15-year-old at the London Games. Pragmatism won out, a decision that ended with her atop the medal stand once again. "They're jogging my memory about 20 years ago, and I'm trying to recall and say what I remember because some little girl who probably wasn't born yet is watching it on TV or something and is wanting to be Katie Ledecky".
Ledecky's time of 8 minutes, 4.79 seconds earned her not only a new world record, but also her fourth gold medal of the Rio games.
Johnston is anxious about her hair, saying, "If my hair turns green, I will send my hair-dye bill to the Olympics".
Then she waited for the rest of the field to finish.
Jazz Carlin has won a second silver medal in the Rio Olympics after she took second in the women's 800m freestyle.
Eight minutes 4.79 seconds after she dived into the water Friday night, Katie Ledecky's hand touched the wall, and then the waiting began.
Ledecky was barely breathing hard. Tears streamed down her face as the national anthem played during the medal ceremony, her history-making week finally over.
Brazil's da Silva 'enjoyed every moment' in Round 1
Rio de Janeiro , Brazil - 11/08/2016. "Brazil is a macho country, a racist country, a homophobic country, a xenophobic country. Silva, who faced discrimination for her skin color, will now be a symbol of hope for generations to come in Brazil.
Stocks close modestly lower
In other energy trading, wholesale gasoline slipped 4 cents to $1.30 a gallon, while heating oil lost a penny to $1.32 a gallon. A sharp sell-off in energy companies has pulled U.S. stock indexes modestly lower, wiping out small gains from the day before.
The same double had racked his 31-year-old body at U.S. Olympic Trials.
That Welsh medal haul now could be broken in Rio with more than a week of competition still remaining.
And there was Schooling, who swam the top qualifying time and beat Phelps in the 100 butterfly in Austin, Texas, on June 3, and who grew up transfixed by Phelps' races.
The most decorated athlete in Olympic history couldn't pull off one of his patented comebacks in the 100-meter butterfly, easily held off by a swimmer a decade younger.
Hosszu got off to a blistering start and led nearly the entire race.
Adam Peaty's bid for a second Olympic gold of the Rio Games remains on course after Great Britain qualified fastest for the 4x100m medley relay final.
With four gold medals at these games and 22 for his career, Phelps has an opportunity to pick up one more before he leaves Rio. While the American team is not yet set, he could be swimming in the men's 4x100 meter medley relay final.
Phelps wound up in a three-way tie for silver along with two longtime rivals, Chad le Clos of South Africa and Laszlo Cseh of Hungary. They all touched in 51.14 seconds, which was actually faster than Phelps' gold medal-winning time in 2012.
"It's what I had", Phelps said. "It's an honor and privilege to even race alongside him".
In a stunning upset Friday, Phelps was beaten in the 100 butterfly.
"It's pretty insane what can happen in eight years", Schooling said. "I'm numb right now", - former National Football League star Michael Carter reflects on his daughter Michelle's shock shot put triumph. "But it hasn't derailed me, I've done it under the stress, made the final, so less stress tomorrow night, the bus turns up, it will be all good".
Justin Gatlin, the sprinter considered the best threat to stop Bolt, won gold at the 2004 Olympics. Victor of three golds and five medals overall in London four years ago, she battled depression and didn't qualify for an individual event in Rio.