[2] Costa was elected to the State Assembly in 1967, as part of the same Republican tide that swept Feldman out of office.
Costa and his running mate, Austin Volk, defeated two freshman Democratic incumbents, Vito Albanese and Arnold E. Brown.
[3] He was re-elected in 1969, running on a ticket with William J. Dorgan; they defeated Democratic challengers Martin T. Durkin and Ernest Allen Cohen by about 10,000 votes.
[4] Costa did not seek re-election to a third term as an Assemblyman in 1971; instead, he ran successfully for a seat on the Bergen County Board of Chosen Freeholders.
In 1937, Costa married Alvera Manewal (1913-2004) in St. Paul's Lutheran Church, Teaneck, New Jersey, in 1937.