Mr Lynch’s resignation came after he survived a no-confidence vote on Monday in which roughly half of his caucus tried to oust him.
The vote ended in a tie, meaning Mr Lynch was able to keep his job as the minority leader of the Colorado House.
He survived again in a similar vote on Tuesday, but by Wednesday morning, he confirmed his resignation.
“I want it to be clear that I’m not stepping down because I won a close vote of no confidence,” Lynch told lawmakers. “I am stepping down because it’s the right thing to do because I’ve become a distraction for my caucus, and that is getting in the way of the hard work that we have to do in this building.
“I would like this to serve as a reminder to my fellow colleagues. Be careful. Don’t make the same mistake that I made which was to get behind the wheel after I had had too much to drink,” Lynch added. “There is a lot of socialising here, thank God, in my instance, there was no damage done. I will tell you personally it has been life-changing.”
Weeks before becoming House GOP leader, Lynch was arrested for a DUI, The Denver Post reported.
The Colorado state rep was pulled over by a State Patrol trooper after he was caught speeding at 90 miles per hour in a 75 mph zone on Interstate 25, the report stated.
After stepping out of the car, the trooper said he smelled alcohol on Mr Lynch, who then admitted he had a firearm on him, the report added.
Mr Lynch then reportedly went to reach for the firearm—prompting the officer to tell him that “pulling a gun out of your pocket when in contact with the police was, in fact, a big deal and people get shot that way,” according to a Colorado State Patrol report obtained by The Denver Post.
Video released of the incident shows that before his arrest, Mr Lynch told the trooper “You do not understand how much I work for you guys” and asked to “keep the press out of this.” He also asked the trooper to call a lobbyist for the State Patrol before backtracking and admitting who he was.
The lawmaker has denied that he asked for preferential treatment, saying he only meant to give those he worked with a heads-up.
Mr Lynch pleaded guilty to driving while ability impaired and gun possession while drunk and was sentenced to 18 months probation and monitored sobriety checks.
He remains on probation but has come under fire for failing to reveal his arrest before The Denver Post’s report emerged on 17 January.
Caucus members have argued that Mr Lynch’s arrest, along with the lack of disclosure since amounted to failed leadership and tarnished the party’s reputation.
“It’s about time. The House Republicans should elect anyone who has NOT been convicted of driving while drunk and broke faith with voters and colleagues by covering it up,” the Colorado Republican party said in a post on X on Wednesday in response to news of Mr Lynch’s resignation.
A vote to elect a new minority leader will be held on Thursday morning.
Mr Lynch is also currently running for Congress in Colorado’s 4th District, a hotly contested race recently joined by Republican Rep Lauren Boebert after she announced she was switching districts.