"This woman is tough. This woman is resilient. This woman is a leader and I am confident she will lead the department on day one," said Mayor Breed.
"I love this city, this department and I love being of service," Nicholson said at the press conference.
RELATED: San Francisco Fire Chief Joanne Hayes-White announces her retirement
She has the support of the current chief, Joanne Hayes White, who said she wholeheartedly supports the selection and promises a smooth transition.
"We will work shoulder to shoulder to make sure this city is safe and protected. That is what we commit to and what the city deserves," said Chief White.
One of Nicholson's first priorities will be to tackle the homeless issue with Mayor Breed.
"Our call volume has gone way up due to the opioid and homelessness crisis. I think there are many ways we can collaborate and work to get people services and off the street. That is a huge priority right there," Nicholson explained.
She also wants to improve the city's disaster preparedness plan.
Nicholson says she can relate to the people she serves. She was one of six firefighters who was burned in an arson fire in 2009.
"I get what people go through on the fire side and on the EMS side. We see people on the worse day of their lives."
She has not been sworn in yet. White will stay on until her retirement in May.
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The new fire chief of San Francisco Jeanine Nicholson. pic.twitter.com/An2kDWyacZ— Amy Hollyfield (@amyhollyfield) March 13, 2019