After winning his second premiership at Hawthorn in 2013, Franklin moved to Sydney via free agency on a nine-year, $10 million deal, before representing Australia in the 2013 International Rules Series.

Franklin was born in Perth, Western Australia, into a family of Indigenous Australian heritage (Noongar-Wajuk)[8] and grew up in Dowerin supporting the Melbourne Football Club.

[10] He played one senior game for the Perth Football Club in 2004, kicking one goal,[14] and represented Western Australia at the 2004 AFL Under 18 Championships.

In a 2012 interview on the Fox Footy program On the Couch, Franklin admitted that his "free spirit" probably scared a few clubs away from selecting him that year.

After injuring his ankle and hand early in the 2006 pre-season, Franklin made his way back to senior level through the VFL and returned in round 9 against the Sydney Swans.

On 13 July 2006 Franklin signed a two-year deal to remain at Hawthorn after being linked with clubs such as Essendon, Fremantle and the West Coast Eagles.

Franklin was named as full forward in the 2008 All-Australian team, his first ever selection; he then received his first Peter Crimmins Medal for his outstanding season.

[26] In round 10, Franklin was suspended for the third time in eight matches for a head-high bump on Sydney Swans' defender Martin Mattner.

[29][30] Franklin kicked five goals in Round 17 against St Kilda after returning from an ankle injury;[31] despite his performance, the Saints forced a draw during the final seconds of the match.

In round 22, Franklin kicked six goals against Collingwood,[32] helping the Hawks clinch a three-point come-from-behind victory against the eventual premiers.

He continued his consistent goalkicking form for the remainder of the year, including a season-high eight goals in a club-record 165-point win against a young Port Adelaide side at the MCG in Round 21.

Franklin went on to win his second Coleman Medal that year with 71 goals, despite spending a significant amount of time further up the ground.

While footage of the incident suggested possible damage to his anterior cruciate ligament, scans later revealed that he had instead suffered bone bruising and bleeding; nevertheless, most observers considered Franklin's season to be over following the loss.

[33] However, he dramatically reversed his fortunes in round 10 when he kicked a career-high thirteen goals in a 115-point drubbing of North Melbourne at Aurora Stadium.

[35] However, Franklin suffered a hamstring injury the week before and continued to play, before injuring it further in the Giants game which, along with an illness, caused him to miss six matches.

[36] Franklin returned against Sydney at the SCG in round 22, kicking four goals in a seven-point come-from-behind victory against the eventual premiers, including three in the second quarter.

[43] Franklin's manager at the time, Liam Pickering, also revealed that the nine-year contract was so back-ended that he would be making less money with the Swans in 2014–15 than he was at Hawthorn in 2013.

Franklin officially joined the Sydney Swans on 8 October 2013, a week after the move was first announced, after Hawthorn decided against matching the offer made to the restricted free agent.

[46] Prior to the 2014 season, his first as a Swan, Franklin opted to continue wearing the number 23 guernsey that he previously wore for Hawthorn.

Franklin's best game of the season came in round 21 against St Kilda at Etihad Stadium, where he recorded an equal personal-best 28 disposals, nine marks and six goals in a 70-point win.

[51] Franklin kicked five goals in the six-point loss to Hawthorn, overtaking Bernie Quinlan to climb into the top ten highest goalkickers in VFL/AFL history.

Franklin won the Brett Kirk Medal (along with Callan Ward) as the best player afield in the Swans' Sydney Derby win in round 17, kicking four goals.

Franklin opened the 2018 season with his largest opening-round haul of eight goals against West Coast in the first AFL match at Optus Stadium.

[58] Franklin won his second Brett Kirk Medal as best afield in the Swans' Sydney Derby win in round 22, kicking five goals to overtake Leigh Matthews as the eighth-highest goalkicker in VFL/AFL history,[59] before missing the final home-and-away match with a groin injury.

[60] Franklin was held goalless for only the second time that year in the elimination final loss to Greater Western Sydney as he dealt with a hip problem.

[64] After a slow start to the 2019 season owing largely to an injury-interrupted pre-season,[65][66] Franklin kicked four goals in round 5 against Richmond at Marvel Stadium, overtaking Matthew Lloyd to become the seventh-highest goalkicker in VFL/AFL history.

[76] In the lead-up to his 300th game, Franklin said he was "very confident" he had plenty of good football left in him despite his injuries, and that he fully intended on seeing out the final three years of his nine-year contract with Sydney; he also said that he had his sights set on reaching the 350-game and 1000-goal milestones in that time, becoming the first player to achieve both.

[78] In January, Franklin underwent an arthroscope on his right knee after experiencing discomfort; the club estimated he would resume full training in ten weeks, placing him in doubt for Sydney's round 1 match against Adelaide.

[83][84][85][86][87] In January, Franklin was "probably only a week off stepping back into the (Swans') full program" before suffering calf tightness;[88][89][90] by March, he had begun to gradually rejoin training, but his return date was still unclear.

[105][106][107] Following retirement from his football career in 2023, Franklin settled on the Gold Coast with his family and works in an ambassadorial role for the AFL in Queensland.