Siemering was born in San Francisco and was raised in Lodi, California,[1][2] where he attended and played high school football at Lodi High School. During his senior season as a center, the Lodi Flames went undefeated.[2] He graduated in 1928. Also during this time, Siemering played semi-pro baseball for the Sacramento Stallions.[3]
Siemering had another winning record in 1948 and went 7–3–1. However, he is best known for his 1949 Pacific team that went an undefeated at 11–0. The team came close to losing only once in 1949, when it defeated San Francisco in the first game of the season, 7–6. The Tigers outscored their opponents 575–66, led the nation in offense, and were ranked as high as tenth in the AP Poll.[1] During the season, the Tigers scored 75 points or more three times, winning 75–20 over Portland, 88–0 over Cal Poly, and 75–0 over the Hawaii.[6] The team was the 15th college team in history to score 500 or more points in a single season.[3]
During his four-year tenure at Pacific, Siemering went 35–5–3 with a .849 winning percentage, the best of any head coach in program history.[2] He then coached at Arizona State University in 1951, where he went 6–3–1.[7] Despite the winning record, he was fired after using an ineligible player who used a fake name.[1]
After a brief second stint in high school teaching, Siemering then became the inaugural head coach of Cabrillo College, a two-year community college in Aptos, California.[8] He coached there from 1959 to 1965.[8] While at Cabrillo, he also coached the Seahawks' golf team until 1976.[8] Siemering was inducted into the first class of the University of the Pacific Athletic Hall of Fame in 1982.[1] His 1947 and 1949 teams were inducted later.[4]
Siemering was married to Sophie Siemering, who died in 2001.[1] On July 27, 2009, he died at Watsonville Community Hospital[2] after a fall at his Watsonville, California home.[1]