This is a very big deal for Lee, the former city administrator. He was not one of the favorites because he is a non politician and his name surfaced only after progressives and moderates on the Board of Supervisors appeared deadlocked.
The vote for Lee was unanimous 11-0. The new mayor called it a whirlwind since he had been on a trip to Asia when his name was raised in nomination.
"And I want to thank you for giving me this tremendous and historic opportunity. Not only on behalf of me and my family, but behalf of the Asian community, but all san Franciscans," said Lee.
That was a reoccurring theme for Lee; at the swearing in he again pledged to serve the entire city.
"And I want to say to all of you, I make that pledge that I will do my very, very best to represent all of the communities that you live in, that we cherish, that make this city a great city," said Lee.
But who will he be looking to for guidance? Veteran City Hall campaigner Don Solem, from Solem and Associates, says there are a couple of standouts.
"Rose Pak is chief among them, she's the one who brought him to the dance," said Solem.
The Chinese community organizer Rose Pak was at the day's swearing in ceremony, but says Lee's decades at City Hall have already prepared him.
"He has been in the trenches working for the last 35 years making our community and this city a better place," said Pak.
Another long time supporter is former Mayor Willie Brown who promoted Lee through a number of departments.
"I made him city purchaser, I made him the head of the Department of Public Works, gave him all the odd jobs," said Brown.
Lee wound up as city administrator and thought he would remain there, until a deal was made that allows him to become the interim mayor for a year. And then if he doesn't run for re-election, he can go back to his old job.
"I present myself to you as a mayor for everyone. A mayor for the neighborhoods, for downtown, for business, for labor, for the powerless, and the powerful, for the left, the right, and everyone in between, for everyone. I will be a mayor that tackles things head on and moves the bar forward. I will be your mayor. Thank you very much," said Lee.
One of the progressives on the board said he felt the progressives have lost control of San Francisco, but they all voted for Lee. Lee now will have to spend some of that political capitol has he faces a tough budget and what promises to be a contentious struggle over who should be the next chief of police.