He played college basketball for the Michigan State Spartans, earning consensus second-team All-American honors.

He worked part-time at a Dayton bowling alley and, after graduation, for a construction company and at a junkyard for six months before joining the U.S. Marine Corps[2] during the Korean War.

[1] After completing his military commitment, Green enrolled at Michigan State in 1955, and played on the 1955–56 Spartans' freshman team.

[4] They advanced to the NCAA tournament semifinal game, which they lost in triple overtime to eventual champion North Carolina despite Green's 19 rebounds and eight blocked shots.

[4] In 1958–59, he led the Spartans to another Big Ten title and a 19–4 record, falling a game short of the NCAA Final Four.

[3] Green's career rebounding average was 16.4 per game, topped in Big Ten history by only hall-of-famer Jerry Lucas' 17.2.

[9] In his rookie season of 1959–60 for the Knicks, during which he turned age 26, he played nearly 18 minutes per game, averaging 7.0 points and 7.8 rebounds.

[9] In February 1962, he set Knicks team record with three consecutive games of 20 or more rebounds (since tied by Walt Bellamy, Willis Reed and Tyson Chandler).

[12] He was traded along with Johnny Egan, Jim Barnes and cash from the Knicks to the Baltimore Bullets for Walt Bellamy on November 1, 1965.

However, just when it appeared Green's NBA career might be over after 10 seasons, in September 1969 he called Cincinnati Royals coach Bob Cousy and asked for a tryout.

On December 20, 1970, he had one of his best-ever games, scoring a career-high 39 points in a one-point double-overtime loss[15] to the Detroit Pistons.

[9] Green entered the restaurant business and owned one of the most popular McDonald's franchises in the world in Springfield Gardens, New York, near John F. Kennedy International Airport.