The backing of the party's most visible figure will provide a lift to G.O.P. leaders ahead of next year's midterms but it might not have happened after Grassley criticized Trump's role in the Jan. 6 attack on the U.S. Capitol.
'We have with us tonight a great American patriot. A man who truly loves Iowa,' said Trump before thousands of fans at the Iowa State Fairgrounds.
'He's young, very young guy, he's strong. And he's very handsome.
'He fights like no other. When I've needed him for help, he was always there.'
Grassley joined Trump on stage and thanked him for his endorsement.
'If I didn't accept the endorsement of a person that's got 91% of the Republican voters in Iowa I wouldn't be too smart, he said.
'I'm smart enough to accept that endorsement.'
'We have with us tonight a great American patriot. A man who truly loves Iowa,' said former President Trump as he brought Sen. Chuck Grassley on stage for a formal endorsement
Grassley was spotted being interviewed before Trump's arrival at the rally at Iowa State Fairgrounds in Des Moines. The 88-year-old announced recently that he will run for reelection
Grassley has generally had cordial relations with Trump.
But distance opened between them in the aftermath of the Jan. 6 violence.
Although he ultimately voted not to convict Trump in his second impeachment trial, he was clear that the then president held some responsibility for the violence that unfolded.
'It was a direct, violent attack on our seat of government,' he said in a statement. 'Those who plowed over police barricades, assaulted law enforcement, and desecrated our monument to representative democracy