After entering the United States Military Academy for one year, he returned to resume his career at Stanford University, playing as an end, and also performing for the school's track team.

After his career was ended by a leg injury, Pool served as a player-coach for the Fort Pierce Naval Amphibious Base during the final two years of World War II, while also working as an underwater demolition officer.

His 1943 unit finished undefeated, and in 1944, he made news when he refused to wear jersey number 14 out of respect for Green Bay Packers' standout Don Hutson.

When the conflict ended, Pool officially entered the coaching arena in 1946, serving as an assistant for the All-America Football Conference's Miami Seahawks under Jack Meagher.

After the team had won just one of six contests during its inaugural campaign, Meagher resigned on October 22, with Pool and fellow assistant Hank Crisp taking over as co-head coaches.

After the Seahawks became the Baltimore Colts after the season, Pool stayed with the revamped franchise until accepting an assistant's position under Jim Crowley, who had been named head coach and general manager of the AAFC's Chicago Rockets.

The Spartans finished with a 9–3 record, but Pool departed after the season to enter private business, but stayed connected to the sport as an assistant coach at San Bernardino Valley College.

On March 3, 1950, Pool returned to the professional ranks when his former Bears teammate, Joe Stydahar, hired him as backfield coach of the Los Angeles Rams.

Ridding itself of the earlier problems, the Rams rebounded to win nine of their final 11 games, with the New York Daily News awarding Pool Coach of the Year honors.