Aaron Peskin, a savvy and bombastic politician who served eight years on the Board of Supervisors, including three as president, will announce Monday that he will run for his old seat in the November election.

Peskin’s bid for the District Three supervisor’s seat, which comprises northeast neighborhoods including Chinatown, Nob Hill, Telegraph Hill, Union Square, the Financial District and parts of Russian Hill, will pit him against incumbent Julie Christensen. Mayor Ed Lee appointed her to the board in January to serve out the term of David Chiu after he was elected to the state Assembly.

In addition to the political theater the campaign will surely generate — there is no love lost between Peskin and Christensen, who were once political allies — the election could tip the balance of power on the Board of Supervisors toward its progressive bloc. Currently, moderates outnumber progressives 6-5.

“I didn’t expect to be running for office again,” Peskin said. “It wasn’t something I planned to do. Given how big the (housing) affordability crisis is, I just don’t feel I can sit on the sidelines.” Peskin is eligible to serve again because he has not been a board member for a full, four-year term. He plans to file papers as a candidate Monday.

Peskin said measures he would champion if elected include extending rent control to tenants who live in apartments built after 1979.

Christensen said she is prepared for the contest. “I’ve been running since the day I was appointed,” she said.

“Aaron and I were friends,” she added. “We worked closely together when he was a supervisor. Since he came out of office, he has done a 180 on literally everything we worked on together.”

Peskin said he has the support of Rose Pak, a political power broker who exerts considerable influence in Chinatown. Pak, who helped persuade Lee to run for a full term as mayor after he was appointed to serve out former Mayor and now Lt. Gov. Gavin Newsom’s term, was unhappy that Lee selected Christensen over Planning Commissioner Cindy Wu for the board.

Former Mayor Art Agnos also supports Peskin, who is a past president of the San Francisco Democratic Party Central Committee.

“Aaron is a skilled legislator who will add a strong dimension to the current board that has been missing since he left,” Agnos said.

Christensen, however, will have the current mayor’s support.

Peskin and Christensen both got their start with the Telegraph Hill Dwellers, an influential and often contentious neighborhood association. But they fought in recent years over the construction of the new North Beach branch library, which Christensen championed and Peskin opposed.

No observer of San Francisco politics in recent years is unfamiliar with Peskin — his frequent squabbles with Newsom both at City Hall and in the media played like free entertainment for the city.

Political consultant Nathan Ballard, a spokesman for Newsom when he was mayor, said of Peskin: “I think he’s a brilliant tactician. He is a tireless opponent, like a dog on a bone. He’s a parliamentary genius.”

But, Ballard added: “Peskin stands for nothing. He is known for tearing things down and blocking things. That’s what he’s good at. That’s where his skill set lies.”

Emily Green is a San Francisco Chronicle staff writer. E-mail: egreen@sfchronicle.com Twitter:@emilytgreen