His first championship was the 1937 Northern California Racing Association against such drivers as Duane Carter, Lynn Deister, and Paul Swedberg.

He made the next 11 500s with a best finish of 4th in 1953, the extremely hot race day where he was relieved by Paul Russo.

He qualified on the pole in 1952 in the Cummins Diesel Special, the first turbocharged Indy race car, but it dropped out after 71 laps.

Agabashian won one Championship race, a 100-mile contest at the Fairgrounds in Sacramento, CA in 1949.

After his retirement, Agabashian did color commentary for the Indianapolis Motor Speedway Radio Network, serving from 1959 to 1965 and again from 1973 to 1977.