[1] Underhill graduated from Lloyd High School in Erlanger, Kentucky, where he lettered four times each in basketball, football, track, and baseball.
He received a Bachelor of Science degree in health and physical education from Tennessee Tech in 1964 and earned a Master of Arts degree in guidance and education in 1965 from Western Kentucky University, where he worked as a graduate assistant basketball coach.
[2] Underhill was the most successful coach in Wright State history, with a career total of 356 wins, including leading the team to an NCAA Division II National Championship in the 1982–83 season.
Known for being a strong recruiter, Underhill had several All-Americans at Wright State: Roman Welch (1980), Rodney Benson (1981) Gary Monroe (1983), Fred Moore (1984), Mark Vest (1985 and 1986), Grant Marion (1986) and Andy Warner (1986), and one player selected in the NBA draft (Vitaly Potapenko, 1996).
His 1993 team, led by star Bill Edwards, won the Mid-Continent Conference Tournament title against the University of Illinois at Chicago and advanced to the NCAA Division I men's basketball tournament as a 16-seed matched against Bobby Knight and the 1-seed Indiana Hoosiers.