Allen Jr. graduated from public high school and while studying at Berkeley joined the United States Navy as an Apprentice seaman during World War I.

[1] After graduating from UC Berkeley School of Law in 1922, Allen Jr. was admitted to the California State Bar and commenced practice.

He also served as the President of the California State School Trustees Association from 1936 to 1938, and as a member of the County Republican Central Committee from 1936 to 1944.

[1] In 1942, during World War II, Allen Jr. returned to the Navy, this time serving as a Lieutenant commander.

[4] After his unsuccessful re-election bid, Allen Jr. was appointed as the Under Secretary of Commerce for Transportation on January 5, 1959, serving until 1961.