Cahill was set to move to the United States to start a scholarship. However, after he impressed on trial, he instead signed a two-year deal with Rotherham United at the start of the 2007–08 season. Matlock received no fee for the 20-year-old, but they did manage to negotiate a 10% sell-on clause, three pre-season friendlies with the Millers over a five-year period, and first refusal on any youngsters that Rotherham were prepared to release on loan deals. Cahill was hit with niggling injuries at the start of his Rotherham career. His first appearance for the Millers, came on 6 October 2007 as a 78th-minute substitute in a 3–2 home win over Mansfield Town. After two injuries, Cahill was sent on loan to Conference National side Altrincham on 1 January 2008, where he made 11 appearances, scoring one goal on 8 January in a 2–1 victory over Kidderminster Harriers. He returned to Rotherham United on 12 March, making a further six appearances that season. In October 2008, Cahill joined Northern Premier League Premier Division side Ilkeston Town on a three-month loan deal.
In summer of 2010, Cahill joined Northern Premier League Division One North outfit AFC Fylde from Fleetwood and scored 24 goals for the Coasters as they reached the Play-off Final but lost to Chorley. He left the club in August 2011 to spend a year travelling around the world.
Move to Australia
After moving to Australia in 2011, Cahill joined Sunshine George Cross FC and spent the first half of the 2012 season there, scoring 6 times in 11 appearances in the Victorian State League Division 1, before moving to Victorian Premier League side Richmond SC, where he managed 10 goals from 10 appearances. He then moved to VPL giants Green Gully SC for the start of the 2013 season, but his stay with the western suburbs based club was short lived, returning to Richmond in mid-2013. In the next two and a half seasons, Cahill went on to become Richmond's captain and top goalscorer in both the 2014 and 2015 seasons, the latter resulting in the promotion of the club. In 2014, his 26 goals in 22 matches saw him win the leagues golden boot award. Cahill then joined National Premier Leagues Victoria side Hume City on a two-year deal, but left from Melbourne Knights FC at the end of the season after managing seven goals in 14 appearances. At Knights, Cahill managed eight goals in 22 appearances. In October 2017, he was released by Melbourne Knights. On 2 November 2017 it was announced that Heidelberg United FC had signed Cahill for the 2018 season.
