After just over a year back in Scotland with Heart of Midlothian, Lafferty re-signed for Rangers in August 2018, and he has since had short spells with Sarpsborg 08, Sunderland, Reggina, Kilmarnock and Anorthosis Famagusta.

He made his debut during a 2–1 away league defeat to Crewe Alexandra on 6 August 2005, coming on as an 89th-minute substitute for Garreth O'Connor.

[4] He made his Rangers debut as an 89th-minute substitute during a UEFA Champions League qualifier on 5 August 2008 against FBK Kaunas.

The referee, Stuart Dougal, sent Mulgrew off for violent conduct; however, television pictures showed little contact between the two players.

[9] The case was also referred to the Scottish Football Association's disciplinary committee, who rescinded Mulgrew's red card and gave Lafferty a two-match ban for simulation.

[12] Lafferty scored in Rangers' 4–0 win over Dundee United in April 2011,[13] before missing an opportunity in the final Old Firm game of the 2010–11 season at Ibrox in a 0–0 draw.

[17] Lafferty then scored a hat-trick in the final SPL game of the season as Rangers beat Kilmarnock 5–1 and won their third consecutive league title.

[citation needed] In June 2012, Lafferty lodged an objection against his contract being transferred from Rangers to the new company set up by Charles Green.

[23][24] He was unable to play in the league match against Grasshoppers on 15 July because the Scottish Football Association refused to provide clearance for the transfer, having received an objection from Rangers' owner Charles Green.

[25] On 20 July, Lafferty received provisional international clearance from FIFA which allowed him to play while arbitration over his move from Rangers continued.

However, club president Maurizio Zamparini called him an "out-of-control womaniser" and claimed that this lifestyle resulted in him being sold.

[27] On 27 June 2014, Lafferty signed a three-year contract with Norwich City of the Football League Championship with an option for an extra year.

[29] Lafferty made his debut for the team on 10 August, as they began the season with a 1–0 defeat away to Wolverhampton Wanderers, replacing Steven Whittaker for the last 14 minutes of the game.

[30] Six days later he made his first start in his first game at Carrow Road, lasting 67 minutes of a 3–0 win over Watford before being replaced by Elliott Bennett.

He scored his first goal of the 2015–16 season in a 3–0 League Cup victory against West Bromwich Albion,[35] but found regular games hard to come by.

In November 2015, Leeds United head coach Steve Evans revealed he had inquired about the availability of Lafferty on loan.

[36] However, Lafferty remained with Norwich until 24 March 2016, when he joined Championship club Birmingham City on loan until the end of the season.

[37] He returned from international duty with a groin injury,[38] but was fit to start Birmingham's match against Brighton & Hove Albion on 5 April.

[41] He made his debut on 18 July in the group stage of the Scottish League Cup, scoring the only goal away to Elgin City.

In the league season, Lafferty scored 12 times as Hearts finished 6th; this made him the Premiership's fourth highest scorer.

Later in 2006, he received his first senior Northern Ireland call-up on a post-season trip to the United States to play friendly games against Romania and Uruguay.

[72] In the following game, against Hungary three days later, he scored a stoppage-time equaliser in a 1–1 draw to keep Northern Ireland top of their group.

[77] He married former Miss Scotland Nicola Mimnagh at St Margaret's Roman Catholic Church, in Johnstone, Renfrewshire, in June 2012.

[80][81] In September 2022, Kilmarnock launched an investigation after video evidence emerged of Lafferty apparently making a sectarian remark in a nightclub.