The United Auto Workers' international executive board made acting President Rory Gamble the union's official leader on Thursday.
Gamble, 64, will serve until the UAW's June 2022 convention.
Former UAW President Gary Jones passed the torch to Gamble in November amid an escalating federal corruption probe. In August, agents from the FBI, IRS and Labor Department raided Jones' home, gathering evidence.
"This is an honor to complete my career and serve the members of this great union in this capacity," Gamble said in a statement on Thursday. "This wasn't planned and it is a tall order. There are difficult decisions that will need to be made in the coming months for our members. But I promise one thing, when I retire and turn over this office, we will deliver a clean union on solid footing."
When he was made acting head last month, Gamble vowed to look at "every inch" of the union to put an end to corruption scandals that have engulfed former and current officials.
"We're going to be looking at every inch of this union to make sure we embrace tight controls," acting head Rory Gamble told Reuters. "We need to make sure we have standards that stop this thing from happening again."