Ellenson was the line coach for the Miami Senior High School Stingarees football team from 1947 to 1949. He then became an assistant for the
Miami Hurricanes football team at the
University of Miami, serving under head coach
Andy Gustafson from 1950 to 1958. After the 1958 season, he decided to quit coaching and sought a new career in real estate. Afterward, Ellenson left coaching altogether and became an associate athletic director under Graves and the executive director of Gators Boosters, Inc., the fund-raising arm of the
University Athletic Association.
Pep talks Ellenson was hugely popular among the Gators players, and served as the team's chief motivational speaker during the 1960s and beyond. After the Gators struggled to a 1–2 record to begin the 1962 season, Ellenson wrote a letter to each member of the team detailing his World War II experiences and encouraging them to play harder: "You'll be a better man for it, and the next adversity won't be so tough." Players and coaches credit "The Letter" for inspiring the team to beat several tough opponents and end the season with a bowl victory. When
Buster Bishop, the coach of the
Florida Gators men's golf team, fell ill immediately before the 1968 NCAA national tournament, Ellenson accompanied the golfers to the tournament in
Las Cruces, New Mexico in his place. He delivered a memorable pep talk to the team using his favorite "positive molecules" metaphor, and the Gators upset the top-ranked Houston Cougars to win the NCAA tournament—the first national championship, in any sport, won by University of Florida athletes. Even after he left the coaching profession in 1970, Ellenson was still called upon to deliver motivational pregame speeches. In
1986, then-Gators coach
Galen Hall invited Ellenson to give a pregame talk before the 3–4 Gators faced the 7–0 and 5th-ranked
Auburn Tigers. Florida won 18–17 in what is still considered one of the greatest games in
Florida Field history.
Steve Spurrier had been the Gators' award-winning quarterback while Ellenson was an assistant coach in the 1960s. When Spurrier was the head coach at
Duke in the late 1980s, he twice had Ellenson give pep talks to his team before traditional rivalry games. Duke won on both occasions. When Spurrier returned to his alma mater in 1990 to become the Gators' head coach, he again invited Ellenson to deliver inspirational talks before big games. The Gators went 4–0 in those contests. == Death and legacy ==