Harrington led the Roos to a NCAA Division III school record 11-6 record during the 2018 season that saw SUNY Canton qualify for the ECAC Tournament for the second time in the program's history. The team also earned its first victory v. SUNY Potsdam in program history behind a season-high 20 save performance from Kody Kocsis. Kocsis was a two-time ECAC Defensive Player of the Week, while Brad Sandroni earned ECAC Rookie of the WEek honors once. The Roos ranked ninth in all of NCAA D-III in ground balls per game, while ranking in the top 35 in saves, saves per game and shot percentage.

Academically, five members of the team were named to the ECAC President's Honor Roll, seven were recognized on the Academic Honor Roll and six student-athletes were named to the USCAA All-Academic Team.

Harrington led the Roos to an 8-6 record during the 2016 season, more than doubling the previous season's win total as the won the inaugural USCAA Classic Championship. During the 2013 season he led the team to a 6-6 record and their first appearance in the Eastern College Athletic Conference Tournament where the game was canceled due to lightning.

Harrington has an extensive lacrosse coaching resume, including serving as an assistant coach at three NCAA colleges – St. Lawrence University, Mars Hill College, and Holy Cross. He helped lead Holy Cross to their most wins in college history in 2006-07. Mars Hill posted their first winning season in 2005-06 with Harrington assisting. And Harrington was on the St. Lawrence University staff that guided the Saints to the 2004 UCAA Conference Regular Season Championship. Harrington has also served as the Canton High School boys varsity lacrosse coach and has been involved with lacrosse at every level.

Harrington was a four-year standout lacrosse player at Nazareth College where he earned a bachelor’s degree in business administration. Prior to joining the Golden Flyers, Harrington was one of the top attackmen in Section 10 earning all-Northern and Most Valuable Player honors at Canton Central School.

Harrington was inducted into the Canton Central Hall of Fame in 2015.