Speaking to about 50 supporters at a rally at 14th Street and Broadway Thursday morning, Siegel said he will focus on social and economic justice, which he said are "the key to creating a safe city."
Siegel said he will protect city workers from what he described as "attacks on their wages and benefits" and create an Oakland "free from racial profiling, gang injunctions and youth curfews."
According to Siegel's campaign fact sheet, he served as president of the University of California at Berkeley's student government in the 1960s, graduated from the university's law school and helped lead the local anti-Vietnam War movement.
Siegel previously served as president of the Oakland school board and the Oakland Housing Authority Commission.
In addition to Quan, who was elected in 2010 and is seeking re-election, the field of candidates includes City Councilwoman Libby Schaaf, college professor and political commentator Joe Tuman and former Port of Oakland commissioner Bryan Parker.