Corey O’Connor prevailed in his bid to oust Mayor Ed Gainey of Pittsburgh in the Democratic primary on Tuesday, dealing a major blow to the activist left in a city where progressives had until recently been ascendant.

O’Connor, the Allegheny County controller and a centrist challenger, defeated Gainey, the first-term incumbent aligned with the far left, by a significant six-point margin, 53-47%, on Tuesday evening with most of the vote counted.

“We built this campaign with and for the people of this city, neighborhood by neighborhood,” O’Connor said in a social media post on Tuesday night. “I’m proud to be your Democratic nominee for Mayor. I’m ready to get to work, and I’m grateful to have you with me as we take the next steps forward, together.”

The primary, which drew national attention in the final weeks, grew increasingly acrimonious — featuring particularly sharp divisions over Israel as well as antisemitism that served as a prelude for the sort of intra-Democratic clashes poised to emerge in several races for federal office next year.

During his tenure, Gainey, who had likewise unseated an incumbent when he was elected as Pittsburgh’s first Black mayor four years ago, drew frequent criticism from the city’s Jewish leaders over his alleged lack of outreach and for a record of offensive commentary on Israel’s war in Gaza, among other issues.

O’Connor, for his part, touted his long-standing ties to Pittsburgh’s sizable and politically active Jewish community, while reiterating his support for Israel and condemning rising antisemitism during the campaign.

Previously, O’Connor, the son of a former mayor of Pittsburgh, served on the City Council representing the heavily Jewish neighborhood of Squirrel Hill — where he was also raised.

O’Connor will face Tony Moreno, the Republican nominee, in the November election, but the race is not expected to be competitive as Pittsburgh is a heavily Democratic city.