It was the first time in any individual sports event at the Olympics that the same athletes won gold, silver and bronze in a specific event at consecutive Games.
After he won, Crouser held up a card to a camera that read "Grandpa, we did it, 2020 Olympic champion".
Wearing shades and a hat with the U.S. flag emblazoned on it, Crouser, who broke the world record in June with a 23.37 mark, started the final in blistering fashion, breaking his Olympic record on his first attempt and then improving on it with his second.
"My mindset was really good going in," Crouser said. "The key was getting a big one (throw) early. I managed to do that."
For a moment, it looked like his own world record was in danger of falling.
He calmed down slightly in his later attempts before unleashing a 23.30m throw with his last attempt, breaking his Olympic record again, and coming within a whisker of the world record.
"I had solidified the win by the end so I got a little more aggressive and chased that bigger throw and finally connected with it," he said.
This is only the third time that an athlete has broken the Olympic record three times during the shot put competition.
Crouser donned a cowboy hat afterwards and celebrated with his countryman Kovacs, as they both draped the U.S. flag on their backs.
Kovacs was pleased with his silver.
"Of course you always (want to) come back with all the gold, but I had one of my best throws of all time. It feels like a privilege and an honour to come back with a medal," he said.
Walsh said he hoped for a better result.
"I definitely wanted a different kind of medal," he said. "I gave myself the best chance out there today to throw far and almost got it. That's all I can ask for."
Walsh said that the rivalry between the three athletes has pushed them to be better.
"Between the three of us we're always pushing each other," he said.
"We're all searching for that little bit (more) and Ryan at the moment has got it."
(Reporting by Omar Mohammed; Additional reporting by Nick Mulvenney; Editing by Himani Sarkar & Shri Navaratnam) ((firstname.lastname@example.org; +254 20 499 1232; Reuters Messaging: email@example.com))