district of Detroit, Allen was the son of Loretta M. and Earl Raymond Allen, who was recorded in the 1920 and 1930 U.S. census records for Wayne County, Michigan as working as a chauffeur to a private family. He earned varsity letters in football, track and basketball at Lake Shore High School in St. Clair Shores, Michigan; having graduated in 1940. Allen went to Alma College in Alma, Michigan and later at Marquette University in Milwaukee, where he was sent as an officer trainee in the United States Navy's V-12 Navy College Training Program. He graduated with a Bachelor of Science in education from Michigan State Normal College—now known as Eastern Michigan University—in Ypsilanti and then attended the University of Michigan in Ann Arbor, where he earned a Master of Science degree in physical education in 1947. Coaching career Morningside Allen was the head football coach at Morningside College in Sioux City, Iowa. The Morningside team was called the Chiefs at that time. He held that position for three seasons, from 1948 through 1950. His coaching record at Morningside was 16–11–2. Whittier Allen was the head football coach at Whittier College in Whittier, California for six seasons, where he was 32–22–5 from 1951 through 1956. He was also the head baseball coach there from 1952 to 1957. Assistant coach in the NFL Allen joined the Los Angeles Rams staff in 1957, under fellow Hall of Fame coach Sid Gillman. Allen was dismissed after one season and, after he resided in Los Angeles out of football for several months, George Halas, founding owner and head coach of the Chicago Bears, brought him to Chicago during the 1958 season. The original purpose of Allen's hiring was to scout the Rams, whom the Bears would play twice during the season; Allen was asked for insights into Gillman's, and the Rams', offensive strategy and signals. Allen's thoroughness and attention to detail so impressed Halas that he eventually earned a full-time position on the coaching staff. During the latter stages of the 1962 season Allen replaced veteran Clark Shaughnessy as Halas' top defensive assistant, effectively making him the Bears' defensive coordinator. His defensive schemes and tactics—and his strong motivational skills—helped make the Bears' unit one of the stingiest of its era. Allen's presence also had a formative effect on such future Hall of Fame players as linebacker Bill George and end Doug Atkins during their