Limerick Gaffney started his career at League of Ireland First Division team
Mervue United before joining Premier League team
Limerick in July 2011. He completed his studies at the
Galway-Mayo Institute of Technology while playing in Ireland.
Cambridge United On 25 November 2014 Gaffney agreed a move to
League Two club
Cambridge United when the transfer window opened. His first season was beset with injury and he made his
Football League debut on 26 September 2015, replacing
Conor Newton in the 81st minute in a 1–0 win against
Stevenage at the
Abbey Stadium providing the cross from which Cambridge scored. Gaffney went on to score twice on his first start for
Cambridge United in the 3–2 away win over
Yeovil Town on 23 October.
Bristol Rovers On 14 January 2016, Gaffney moved permanently to
League Two club
Bristol Rovers after a successful loan spell. After scoring five goals in seven games for the West Country Club. Gaffney ended the season with a tally of eight league goals as he played a useful part in the club's promotion to
Football League One. Gaffney scored his first goal in
Sky Bet League One and his first for the club since 16 April 2016 on 1 October 2016 with his club's first goal in a dramatic 3–2 win over
Northampton Town. Rory scored his first goal since 10 December 2016 in the 4–2 victory over
Bury on 11 March 2017 in a 2–0 victory over
Southend United. He scored his second goal in a week scoring what would prove to be the winner in a 2–1 victory over
Chesterfield taking his season total to four league goals. Gaffney ended the season with a total of nine goals including two in a 4–2 loss vs
Peterborough United as his side narrowly missed the playoffs. Gaffney scored his first goal of the 2017–18 season to make it 3–1 in a 4–1 defeat to Peterborough United on 12 August 2017 when he headed home a
Lee Brown cross at the back post.
Salford City In June 2018 he joined
National League side
Salford City on a three-year contract. He made his debut in the opening match of the 2018–19 season on 4 August as Salford drew 1–1 at home to
Leyton Orient. His first season with the club ended in success as Salford City won promotion to the Football League for the first time in their history in their first season in the fifth tier. Gaffney scored a penalty in a play-off semi-final shootout victory against
Eastleigh and came off of the bench in the 3–0 final victory over
AFC Fylde.
Walsall (loan) On 31 August 2019 he joined
Walsall on loan for the remainder of the
2019–20 season, linking up with former-Rovers manager
Darrell Clarke. After 25 appearances, scoring just once, Gaffney had his loan terminated in February 2020.
Shamrock Rovers On 24 February 2020, Salford City announced they and Gaffney had mutually parted ways and he had left the club and later that day signed for
Shamrock Rovers. In April 2021, Gaffney opened his scoring for the club with a late equaliser against
Sligo Rovers. Gaffney scored twice at
KF Teuta Durrës in a
2021–22 UEFA Europa Conference League tie where Rovers won 2-0 In the
2022–23 UEFA Champions League Gaffney scored against
Hibernians F.C. When Gaffney scored at
KF Shkupi in the
2022–23 UEFA Europa League he completed his scoring record in all three main European club competitions At the end of the
2022 season, a season in which Shamrock Rovers won the league for a third consecutive season, Gaffney was named the
PFAI Players' Player of the Year at the end of season awards.He was also awarded the SSE Airtricity League Player of the Year award Having originally being allowed leave the club at the end of the 2024 season following the end of his contract, Gaffney returned to
Shamrock Rovers on 21 February 2025, 3 competitive games into the season, after proving his fitness following 10 months without a competitive appearance. On 4 April 2025, Gaffney scored his first goal since his new contract in a 1-0 win away to
Galway United. He then went on an impressive goal scoring run netting against
Cork City,
Waterford,
Wexford St Joseph's and twice against
Derry City and
Ballkani in the space of 2 months. On 2 December 2025, he was named as
League of Ireland Player of the Month for November, after scoring twice in his side's
2025 FAI Cup final win over
Cork City. ==Career statistics==