A couple dozen protesters rallied Monday outside San Jose City Hall, in support of the former BART police officer.
Mehserle was convicted last month of involuntary manslaughter in the shooting death of unarmed passenger Oscar Grant. One of the demonstrators was Mehserle's father, Todd.
"As tragic as this whole event's been, maybe it's time for people to get a little more sense of who Johannes really, truly is. So we come out," said Todd Mehserle.
The protesters say they plan to rally every week or two around the Bay Area, until Mehserle is freed.
Sentencing is set for November.
He faces five to 14 years in prison.