Gillheeney went 6-5 with a 3.86 ERA in 13 starts for the Wolfpack in 2009, striking out 75 and walked 34. In one of the more memorable performances of the 2009 campaign, Gillheeney scattered seven hits in seven shutout innings May 8 vs. North Carolina, striking out 10 in a 3-0 win over the then-top-ranked Tar Heels. Following the year, Gillheeney was voted second-team All-ACC by the league's head coaches.
Gillheeney moved into the starting role this past season after spending his sophomore year in 2008 as the Pack's closer. That year, he went 2-0 and recorded 10 saves in 21 appearances, posting a 1.12 ERA. He struck out 42 and walked 12.
Following the 2008 season, Gillheeney was named third-team All-America by the NCBWA and was voted first-team All-ACC, becoming the third NC State closer to earn first-team all-conference honors, joining Jamie Wolkosky (1992) and Joey Devine (2003-04-05). Gillheeney's performance as a closer earned him a spot on the National College Baseball Writers Association's preseason watch list for the Stopper of the Year Award for 2009.
As a freshman in 2007, Gillheeney split time between the starting rotation and the bullpen, finishing with a 4-3 record with one save in 19 appearances (nine starts). Gillheeney notched 46 strikeouts and 23 walks in 63 2/3 innings with a 6.36 ERA.