Four progressive San Francisco supervisors have broken ranks with hometown U.S. Sen. Dianne Feinstein — the city’s most prominent and long-standing Democratic politician — and instead endorsed her challenger, Kevin de Leon.

Supervisors Jane Kim, Hillary Ronen, Aaron Peskin and Norman Yee all threw their support behind de Leon, the state Senate president pro tem who jumped into the race in October, to long-shot odds.

De Leon gained popularity crusading against the policies of President Trump this year, and his views on immigrant rights, climate change and single-payer health care are picking up support in the Bay Area, campaign spokesman Roger Salazar said.

Raised in Los Angeles by an immigrant mother who cleaned houses, de Leon has cast himself as the humble alternative to Feinstein, a resident of the city’s posh Pacific Heights neighborhood.

Feinstein’s political consultant, Bill Carrick, rejected the notion that De Leon is the more progressive candidate, and said he wasn’t intimidated by the supervisors’ endorsements.

“San Francisco is a politically active city, and everyone has opinions,” Carrick said.

De Leon supported District Nine supervisor candidate Joshua Arce in last year’s campaign over Ronen, but that didn’t stop her from backing him this time around.

Ronen, who declined to comment, has evidently forgiven the slight.

— Rachel Swan

Email: cityinsider@sfchronicle.com, rswan@sfchronicle.com Twitter: @sfcityinsider, @rachelsawn