Fain’s victory is part of a larger upheaval on the union’s 14-person International Executive Board. Candidates who ran on Fain’s UAW Members United reform caucus won each of the seven races they contested, while another independent candidate won an eighth seat.

Still, Fain’s victory was not without controversy.

He came in second during the first round of voting, but advanced with Curry to the runoff after none of the five candidates received a majority of votes.

The runoff results were delayed by nearly two weeks after the court-appointed monitor overseeing the count had to pause to verify nearly 1,600 challenged ballots. As the final tally commenced, Curry’s team filed a protest with the monitor, arguing numerous issues “call the election into question and require immediate investigation.” The monitor later said Curry’s team demanded a halt to the vote-count and that another runoff take place.

Curry’s team argued that “tens of thousands of ballots” were returned to the union as undeliverable and questioned whether the monitor’s office made “all reasonable efforts” to ensure those members could vote.

They also called into question the validity of Daniel Vicente’s victory as director of Region 9, which represents workers in New York, New Jersey and Pennsylvania. Curry argued that Vicente was not able to run because he had not paid the dues necessary to be a UAW member in good standing until after the original November vote.

Curry also said campaign rules were not consistently enforced and that campaign donations to his opponent came from employers with whom the union has a bargaining relationship, which would be against the rules.

The monitor dismissed Curry’s calls for a new election, although it’s unclear if he’ll take additional steps to challenge the results.

In the meantime, Fain will have to build out his staff within a UAW bureaucracy he criticized as a candidate. According to a transition memo first reported by the Detroit Free Press, he plans big shakeups within the union’s staff.

Masters said whom Fain surrounds himself with, and whom he places on bargaining committees this fall with the automakers, will be key.

“It’s going to be very interesting,” he said. “I would watch very carefully who he puts in key positions because that will tell you an awful lot.”