In 2012–13, Harrington was sidelined with a broken leg during UMass' late-season playoff push,[1] but still managed to post 16 points in 21 games prior to her injury, while helping the Minutemen to a top-five ranking for the first time in four years.

With Harrington now an alternate captain, and with her 17 points leading the way among the squad's blueliners, UMass was ranked in the ACHA's top five for the entirety of the season, winding up in second to equal its best placement ever.

At that year's ACHA National Tournament in Newark, Delaware, the Minutemen quickly secured advancement to the semifinals with pool round wins over Liberty and Adrian, followed by Harrington scoring twice in a post-clinch defeat to Robert Morris (IL).

In the semifinals, Massachusetts got revenge on URI for the ECWHL playoffs with a 2–1 victory,[6] although Miami University stopped UMass one win shy of a national title with a 3–1 result in the final.

Included among her career-best 26 points were a four-point outing against Northeastern on October 24, 2014, as well as the game-winning goal against Penn State two weeks prior to that, her first game against PSU since departing that program in 2012.

[14] As with the national university team, Harrington helped the U.S. ball hockey program reach new heights by winning the silver medal, following fourth-place finishes each of the previous five times it had entered the biennial tournament.

Buffalo pulled off a pair of upset victories, over the New York Riveters in the semifinals by a 4–2 count, then 3–2 over the Boston Pride (the defending champions, who had gone 35–4–1 over the two NWHL regular and playoff seasons entering the contest) to capture the Isobel Cup.