The 34-year-old mother of three, who won her second gold medal in Rio five years ago before retiring, returned to the sport in a bid to become the first person to row for Great Britain at the Olympics after having children.
She will partner Polly Swann in the coxless pairs as she seeks a hat-trick of gold medals in the event.
“Today’s announcement is something that when I first thought about a comeback was just like ‘Oh, that’s a nice dream to have’,” Glover told reporters. “It didn’t feel like it was going to happen.
“My reality was staying up all night with the twins, trying to fit in sessions here and there. To be here today I think is in some ways the biggest achievement of my career.
“Before it’s always been about performance and that result at the Olympics. But this was not just getting onto the team but what getting onto the team represents.”
Glover gave birth to boy and girl twins Kit and Bo last year, with the world about to be swept by the COVID-19 pandemic, and also has a two-year-old son Logan.
She said she had wanted to show her children what commitment and passion looked like, but she also struck a chord with a much wider audience.
“It’s amazing how much it just came from saying ‘I’m going to try, and I might fail’.
“I think that makes today just feel like much more of a moment than it ever has done from my other two Olympic Games.
“This feels like a moment I can celebrate and then get really excited and optimistic about what’s to come.”
Team GB announced a rowing team of 24 women and 21 men, including 37 Olympic debutants.
Rio 2016 Olympic coxless four gold medallist Mohamed Sbihi returns as part of the men’s eight, with which he won a bronze in 2012.
Vicky Thornley, a double sculls silver medallist in Rio, will be at her third games in the single sculls.
Additional reporting by PA.