Updated 3:30 p.m.
San Francisco Mayor Ed Lee died early Tuesday morning at Zuckerberg San Francisco General Hospital, ending an unexpected political career that saw him lead the city out of the recession and into an economic boom marked by a deep housing crisis.
Lee, the city's 43rd mayor, passed away at 1:11 a.m. with relatives, friends and colleagues at his side, according to a statement from the mayor's office. Board of Supervisors President London Breed will serve as acting mayor.
An official cause of death was not immediately announced, but a high-ranking city official told KQED that Lee suffered a heart attack at a grocery store late Monday night. An employee at the Safeway on Monterey Avenue said the mayor collapsed there as he was shopping with his wife.
Dr. Susan Ehrlich, CEO of SFGH, said Lee arrived at the hospital in critical condition shortly after 10 p.m. Monday, and staff attempted life-saving measures for several hours until he died.
"Our thoughts and prayers are with his wife, Anita, his two daughters, Brianna and Tania, and his family," the city's statement said.
Breed described Lee, at a press conference at City Hall on Tuesday, as "someone who fought for those in need before himself" and a "dedicated and committed public servant" .
"Our city's values have never been more important," Breed said. "In the months ahead, let's carry on in his honor."
"Flash never mattered to him. Disagreements never deterred him," Breed said. "He was humble and determined, no matter the job he held. He was fair and collaborative, no matter the heat of the moment."
Accolades poured in from elected officials. San Francisco congresswoman Nancy Pelosi called the news "heartbreaking."
“Mayor Lee’s first priority was always the people," Pelosi said. "As a community organizer, civil rights lawyer and hard-working son of an immigrant family of modest means, Ed Lee understood that the strength of a community is measured by its success in meeting the needs of all of its people."
Lee, a Seattle native born to Chinese immigrants, spent the early part of his career as a civil rights attorney. A quiet and measured man, he rose through the ranks of city government after his 1989 appointment as an investigator, helping to enforce San Francisco's first whistleblower law.
Mayor Art Agnos, who first brought Lee into city government, eventually named him director of the city's Human Rights Commission; Lee ultimately served under four mayors until his own appointment to the top job in 2011.
Before that, Lee had become an integral part of city operations: In 2000, he became director of public works; then in 2005, he was named city administrator, a position similar to city manager. After Mayor Gavin Newsom was elected lieutenant governor in 2010, Lee was appointed to lead the city by the Board of Supervisors.
Newsom, who is currently acting governor while Jerry Brown is in Paris, ordered flags at the Capitol and on all state buildings throughout California to be flown at half-staff.
"His intellect, unshakable integrity, boundless optimism and contagious love for San Francisco elevated the City to greater heights," Newsom said in a statement. "He steered San Francisco with an unshakable hand, an indomitable spirit, and a great sense of humor."
Sen. Dianne Feinstein, who served as San Francisco mayor for 10 years starting in 1978, said in a written statement that she is deeply saddened by Lee's death. Feinstein -- who lost her first husband, Bertram Feinstein -- said she is thinking about Lee's family, especially his wife and daughters.
"I know what this is like and wish I could give Anita a hug and express my sorrow," she said. “Ed was an excellent mayor of a great but sometimes challenging city. His equanimity and quiet management style was effective and allowed him to solve problems as they occurred."
California's junior senator, Kamala Harris -- who served as district attorney while Lee was city administrator -- tweeted that she is "deeply saddened by the passing of my friend."
"He was a fierce advocate for civil rights and worked tirelessly for workers’ rights and his leadership will be missed," she wrote.
State Sen. Scott Wiener, a former supervisor who on Monday held a joint appearance with the mayor to tout a new community recycling program, said in a statement that Lee had been "his normal jovial and friendly self" at the event.
"Ed Lee was a kind and decent human being who cared deeply about our city and our community," Wiener added. "... Ed never got the credit he deserved as arguably the most pro-housing mayor in the history of San Francisco, with a huge amount of affordable housing created or approved under his administration."
Supervisor Hillary Ronen, who sits on the board's more liberal wing and often sparred with Lee, said she found common ground working with the mayor on homeless issues over the past year. Ronen said at a recent visit to a navigation center in her district -- a resource for homeless San Franciscans that she and Lee helped set up together -- she was struck by how genuine he was.
"Watching him interact with the residents of the center was a beautiful thing -- he did come from working with low-income people and fighting for the housing rights for members of the Chinese community," Ronen said. "And I saw that whole side of him come out, just the respect and dignity. He had a very, very natural way -- none of it felt put on or fake -- he really cared and you can see that through and through."
Lee, she said, "gave 40 years of his life to this city in various, various positions, and I think we owe him and his family a tremendous gratitude for that."
San Jose Mayor Sam Liccardo told KCBS that Lee was "a good and gracious man at a time when goodness and graciousness aren't common qualities. Nobody loved San Francisco more than Ed, and nobody cared about his community more than Ed did."
Bay Area Rep. Barbara Lee (D-Oakland) issued a statement following Lee's death.
"Even before he was Mayor, Ed was a champion for the people of San Francisco," Barbara Lee said. "As a community organizer and a civil rights attorney, Ed showed his tireless commitment to families and the most vulnerable. And as the first Asian-American mayor of San Francisco, he broke new ground for the city."
Breed, the president of the Board of Supervisors, is now acting mayor, according to the City Charter. The board must now decide whether to back Breed until a special election, which will be held June 5, City Attorney Dennis Herrera said at a press conference at City Hall Tuesday. The elected official will serve until January 2020.
Several members of the board, including Breed, are thought to be considering a run for mayor in 2019. That could complicate the supervisors' choice of an interim mayor. They might prefer to name an interim mayor who would not run for the position next year to avoid pre-empting the voters' choice while also complicating their own political futures.