[3] In 1941, Harkness became a volunteer coach for a group of students at Rensselaer Polytechnic Institute in Troy who were interested in forming a lacrosse club.
Through that year and the next, the team practiced and scrimmaged with Harkness leading the way, eventually playing games against four varsity programs.
World War II led to the disbanding of the team, but when the school formally established a varsity lacrosse program in 1945, Harkness was asked to become its first coach.
Following World War II, RPI President Livingston Houston began looking for a way to re-establish hockey at the Institute, and Harkness was willing to lend his assistance.
After the construction of the Houston Field House was completed in late 1949, the team began play under Harkness in January 1950.
In 1953, the team won its first official Tri-State championship and was invited to the NCAA Tournament for the first time, winning third place.
Though heavy underdogs, Harkness and his team upset traditional powerhouses Michigan and Minnesota to win the 1954 NCAA Championship.
In 1963, Harkness moved to Cornell University, where he replaced Paul Patten as the head coach of the hockey team.
The next season, Cornell again went to the NCAA Tournament, again with 27 victories, but lost to North Dakota in the semifinals before defeating Boston College for third place.
Cornell defeated Michigan Tech in the NCAA Tournament before dropping the championship game to the Denver Pioneers.
[5] Things that are commonplace and obvious today, such as no cigar smoking in the locker room between periods and shorter ice shifts caused a mutiny by the veteran players.
Union College had fielded a hockey team in the early 20th century but had been unable to bounce back from the loss of the program during World War II.
The school began play in NCAA Division III and with Harkness behind the bench, the team was instantly successful.
It was alleged that Harkness had violated NESCAC recruiting rules (and then lied to Union College President Thomas Bonner about it), but there was widespread suspicion on campus that admission standards for hockey players had been compromised.
In the spring of 1978, Harkness was a finalist for the North Dakota head coach position that was ultimately given to John "Gino" Gasparini.