In 2002, Gaffney helped turn a 2–20 Raiders team into the 21–4 Massachusetts Division 2 South Sectional Champions.

After going undrafted, Gaffney joined the 2009 Los Angeles Lakers Las Vegas Summer League team.

[4] Thanks to his strong play in Las Vegas, Gaffney was invited to the 2009–10 Lakers training camp.

[6] Gaffney then played for the Hapoel Gilboa Galil Elyon club in Israel, but, after injuring his foot, returned to the United States for treatment.

[10] Flash officials said they expected him to contribute right away, and, though signing at the All-star break, he produced 11.5 points, 7 rebounds and 2 blocks per game in being named NBDL All-Defensive First Team and honorable mention All-League.

In July 2011 Gaffney was signed by Telekom Baskets Bonn, BBL Germany, playing in the league's All Star game at the midway point of the Baskets' season, then ending the regular season as the only player in the top ten in the league both in blocks (first) and steals (5th), averaging 13 points and 6 rebounds.

In September 2014, Gaffney signed a two-year contract (with a team option for year two) to play with Hapoel Jerusalem B.C.,[15] which won the 2014–15 Championship for the first time in league history.

During the 2015–16 season in which Jerusalem lost in the Championship Finals, Gaffney averaged 10 ppg and 6 rpg and led the league in 2-point percentage while shooting 33% from 3.

[18] On December 2, 2017, Gaffney made his debut in a 95–86 win over Maccabi Rishon LeZion, recording 23 points, five rebounds, three steals and three blocks off the bench.

[22] Gaffney helped Brindisi reach the 2019 LBA Playoffs, where they eventually were eliminated by Dinamo Sassari.

On June 25, 2019, Gaffney returned to Israel for a third stint, signing a one-year deal with Ironi Nahariya.