[5] In 1920, Spence was elected as a Republican Assemblyman from Oakland's 35th district in the California State Assembly,[6] and in January 1925 his name was considered for the position of speaker of the house.
[7][8] Afterwards, he served as private secretary to Governor C. C. Young, accompanying him on a fishing trip to the Yosemite Valley in June 1927.
[14] In September 1930, during the next election, Spence successfully ran for a seat on the Court of Appeal, First District, with an unexpired term ending January 1933, winning over Frank Deasy, presiding judge of the San Francisco Municipal Court.
[15][16][17] In December 1944, Governor Earl Warren appointed Spence as an associate justice of the California Supreme Court,[18] and he began his term on January 2, 1945.
On November 15, 1952, Spence married Frances Davie Horton, a widow in San Francisco.