The former Democrat candidate for US leader read from Michael Wolff’s explosive account of life inside President Trump’s White House, Fire and Fury, as part of a skit starring the likes of John Legend, DJ Khaled and Cardi B.
The Grammy Awards host James Corden was auditioning the musicians - and eventually Ms Clinton - for the audio recording of the best-seller book.
She was revealed as the final audition hopeful before Corden told her she had got the job.
“You think so?,” Ms Clinton replied.
Mr Trump Jr and US United Nations Ambassador Nikki Haley both slammed her appearance on the music awards show via social media.
The president’s son tweeted: “Getting to read a #fakenews book excerpt at the Grammys seems like a great consolation prize for losing the presidency.”
He later added: “The more Hillary goes on television the more the American people realize how awesome it is to have @realDonaldTrump in office.”
Haley wrote: “I have always loved the Grammys but to have artists read the Fire and Fury book killed it.
“Don’t ruin great music with trash. Some of us love music without the politics thrown in it.”
However lots of viewers appeared to disagree, with one calling it the “best segment of the night”.
@cmclymer tweeted: “OMG, Hillary Clinton reading “Fire and Fury” on national television.”
“KaniJJackson posted: “Hillary Clinton reading an excerpt from Fire and Fury book is the best performance I’ve seen all night.”
@MarkCM07 wrote: “Epic @HillaryClinton reading #FireAndFury at the #grammys. You know Trump won’t be able to contain himself.”
It was not Ms Clinton’s first appearance at the Grammys. In 1997 she won for reading her book It Takes a Village.