Born in Washington, D.C. in 1942, Hetzel attended Woodrow Wilson High School (Washington, D.C.) and played for the Tigers during the 1958 season. Hetzel then transferred to Landon School (Bethesda, MD) and was a 3 time Washington Daily News All-Met (following Lew Luce and fellow Washington Metropolitan Basketball Hall of Fame member, George Leftwich, as the only 3-peats). He averaged 24.1 points per game and tallied 1,210 points during his Landon career. On March 2, 1961, undefeated Landon and DeMatha Catholic High School (ranked 1-2 in the city) faced off in Cole Field House before a crowd of 6,400. Hetzel led Landon with 18 points, though Dematha, coached by fellow Washington Metropolitan Basketball Hall of Fame member, Morgan Wootten, won 57-52.
Hetzel attended Davidson College, and was a two time Consensus All-American (1964, 1965) and was a three time Southern Conference Player of the Year (1963-65). He was selected by the San Francisco Warriors with the first pick of the 1965 NBA Draft, and was named to the 1966 NBA All-Rookie Team. He played six seasons in the NBA (1965–71) with five teams, including the 1970-71 Los Angeles Lakers, and scored 4,658 career points.