This is a very unorthodox appointment and according to Gascon, it is also a unique opportunity, which is why he could not turn it down. He was sworn in as San Francisco's district attorney under the city hall rotunda on Sunday.
It has been a whirlwind weekend for the former police chief. The mayor asked him to take the district attorney's job Saturday afternoon. Gascon then turned to his wife for advice.
"She immediately said, 'Where's your heart?' And says, 'Follow your heart,'" he recalled.
Replacing Kamala Harris, who was sworn in as state attorney general last week, was Gavin Newsom's last major decision as mayor. He leaves San Francisco for the Lt. Governor's job on Monday.
Newsom says Gascon emerged as a top pick only after Gascon approached him offering advice about what qualities he would like to see in the new district attorney from a police chief's perspective.
"As I was listening to him, it became clear to me that he was the choice. He didn't know that. He was giving me some good advice. He didn't know how good the advice was," Newsom said.
The mayor hopes Gascon's appointment will bring a level of cooperation between the district attorney's office and the police department that has not been seen in decades. Although Gascon has spent most of his life in law enforcement, he does hold a law degree from Western State University. His time spent practicing law is limited, only a year and a half, but Gascon is undaunted.
"I believe I have the organizational skills and I have the understanding of the criminal justice system not only today, but where we need to be in the future, and I believe that I'm uniquely qualified to bring the two together," he told ABC7.
As to who will run the police department, Assistant Chief Jeff Godown is now acting chief. It is up to the new mayor to decide who will take on the job permanently.
Gascon is San Francisco's first Latino district attorney.
