Born in Termini Imerese in Sicily, Italy, Alaimo received a Bachelor of Arts degree from Ohio Northern University in 1940, and then served as an aviator in the United States Army Air Corps during World War II, from 1941 to 1945.

[2] After the war, Alaimo received a Juris Doctor from Emory University School of Law in 1948 and entered the private practice of law in Atlanta, Georgia from 1948 to 1957, and in Brunswick, Georgia from 1957 to 1971.

[3] On November 29, 1971, President Richard Nixon nominated Alaimo to a new seat on the United States District Court for the Southern District of Georgia created by 84 Stat.

[3] Alaimo was also a member of the Judicial Conference of the United States from 1990 to 1993.

[3] The pace of Alaimo's court earned it the nickname "the Rocket Docket.