Whilst attending Missoula County High School, Rice won both the 800 and mile high-school state titles in his sophomore, junior and senior years.

[2] Greg Rice ran for Notre Dame university track team whilst studying there.

[3] After leaving Notre Dame, Rice was affiliated with the New York Athletic Club[2] His achievements in 1940: American records at 2 and 3 miles; winning the national 5000 m title; and beating Finland's champion athlete Taisto Mäki meant he was the overwhelming winner of the Sullivan Award that year[4][5] On the 28 February 1942 at the AAU indoor championships, Rice set a world indoor best time at three miles of 13:45.7, a time not bettered for 17 years.

[8] His final race was on June 20, 1943, where he came second to the legendary Swedish runner Gunder Hägg over 5000 m at the AAU Championships.

His training for the race had been interrupted by time at sea following his enlisting in the United States Maritime Service six months earlier.