San Francisco Mayor Ed Lee died early Tuesday morning at the age of 65. Lee, who made housing and homelessness top priorities during his career, died at the hospital after suffering a heart attack at a Safeway in San Francisco, The New York Times reports. London Breed, president of the board of supervisors, was sworn into office as acting mayor early this morning. She becomes the city’s first female African-American mayor.

Lee, the city’s first Asian-American mayor, was elected in 2011 after replacing Gavin Newsom, who was elected California’s lieutenant governor.

Lee began his career fighting for affordable housing and was an advocate for immigrants and renters rights in San Francisco's Chinatown, according to the San Francisco Business Times. A young lawyer at the time, Lee went against San Francisco's Housing Authority in 1978 due to unsafe living conditions in a 433-unit apartment property. He led a six-month rent strike, which forced the city to renovate the units and create additional security.

He spent much of his career as mayor pushing for additional middle-class housing, affordable housing and housing for homeless. Earlier this year, he issued an order to speed up the housing application process and called on the city to complete 5,000 new and renovated housing units each year.

In June, he unveiled a budget that would increase spending on homelessness services to $305M from $275M as well as spending for shelter beds. As of June, supportive housing units increased 38% since he took office in 2011 and 7,000 units are expected by the year’s end, according to the San Francisco Examiner. San Francisco Supervisor Malia Cohen told KTVU one of Lee’s latest priorities was to get another 1,000 homeless people off the streets.