Senior deputy Philip Chun Tong is now in custody at the county jail where, until Friday morning, part of his job as a sheriff's deputy was supervising the inmates.
The 36-year-old is accused of robbing the Bank of America on Balboa Street on November 7.
The district attorney says he walked in at about 4:45 p.m. and handed the teller a demand note. The note said he had a weapon, although he never showed one. The teller gave him $1,700 and he left on foot.
"Well, the residents of San Francisco expect their men and women in uniform to uphold themselves with the highest respect for the law," assistant district attorney Alex Bastian said. "The actions of this particular individual, this defendant, are deplorable. There are going to be serious consequences for them."
Investigators used fingerprints on the demand note and bank surveillance video to identify Tong. He was arrested Friday at 7:30 a.m. outside the jail where he works on Seventh Street.
Here's what we know about him -- Tong became a deputy in 2005 and was assigned to the custody division. He's facing two felony charges, second degree burglary and second degree robbery.
"You can go to state prison for up to five years for robbery, it's a violent offense pursuing to the penal code," Bastian said.
Tong is being held on $150,000 bail. He's expected to be arraigned on Monday afternoon.