Tom Rice, a five-term South Carolina incumbent, was beaten in a primary election by Trump-backed challenger Russell Fry, a state legislator.
But another Republican in the state who had criticised Mr Trump, Nancy Mace, comfortably won her vote.
Ms Mace had later visited Trump Tower in a show of loyalty.
Congressional votes were held on Tuesday in Maine, Nevada, North Dakota, South Carolina and Texas.
Mr Rice had been a reliable supporter of Mr Trump until the US Capitol riot on 6 January 2021, when he became one of 10 Republicans who sided with Democrats days later to impeach the outgoing president for inciting insurrection.
Mr Trump was acquitted of the political charge in the Senate. A Democratic-led congressional inquiry is currently conducting public hearings into the Capitol riot, accusing the former president of plotting an attempted coup.
Mr Rice had acknowledged his impeachment vote could end his political career, but had maintained he was following his conscience. He lost on Tuesday night by more than 25 points.
The 10 Republicans who voted to impeach Mr Trump have faced varying outcomes. Liz Cheney and Adam Kinzinger have become vocal Trump critics and currently sit on the US House of Representatives committee that is investigating the Capitol riot. Mr Kinzinger is among those who are not running for re-election. Others are fighting for their political lives.
Ms Mace did not vote to impeach Mr Trump, but she incurred his displeasure by condemning him for the Capitol riot and voting to certify President Joe Biden’s win in the 2020 White House election.
She tried to make amends by filming a video in New York City this year outside Trump Tower to remind her constituents that she was one of the former president’s earliest supporters.
Mr Trump endorsed her opponent, former state legislator Katie Arrington. But Ms Mace comfortably passed the 50% vote threshold needed to avoid a run-off election.
Mr Trump, who turned 76 on Tuesday, had asked supporters to give him two birthday presents by defeating Mr Rice and Ms Mace.
Political analysts expect the winners of the Republican primaries in ruby-red South Carolina to prevail in the election against their Democratic challengers in November’s mid-term elections.
In other results, for the first time Republicans flipped a heavily Hispanic seat in Texas.
During a special election in the 34th district Mayra Flores captured a seat that President Biden won by 13 points in 2020.
The victory comes as Mr Biden’s approval rating fell for a third straight week to 39% in a Reuters/Ipsos opinion poll, as Americans grapple with soaring inflation.