Carlton: 2005–2013 After being overlooked in the National Draft, Betts was recruited to the AFL with pick 3 in the
2004 Pre-Season Draft by the Carlton Football Club. He attracted attention as a lively small forward during the 2005 pre-season, and made his AFL debut in round 1 against the . He kicked 19 goals in 19 games in 2006, playing as a permanent small forward and becoming a fan favourite. Throughout his first four seasons, Betts had a consistent output of roughly a goal per game. From 2009, Betts' goalkicking output increased, kicking 38 goals in 2009, then 42 in 2010 to top Carlton's goal kicking for the first time, while also making the top 10 in the club best and fairest. but rebounded to kick 50 goals for the season, Betts kicked 48 goals in 2012, In that year he led the club's goalkicking, was runner-up in the club best and fairest count and was named in the 40 man
All-Australian shortlist for the second year in a row. Betts kicked 27 goals in 18 games in a 2013 season interrupted by a suspension and a fractured jaw, including five goals in Carlton's two finals. At the end of the season, Betts entered the market as a restricted free agent, and in October he notified Carlton he had accepted a four-year contract understood to be worth about $2 million (AUS) to join the
Adelaide Crows. Carlton had 72 hours to match the Crows offer but declined to do so, allowing the confirmation of Betts' switch to occur on 4 October, the first day of the free agency period. On 26 May 2015, the AFL launched an inquiry into Betts' signing with Adelaide after the outgoing Carlton coach,
Mick Malthouse, claimed to have been told by the current Carlton and former Adelaide CEO Steven Trigg that Adelaide had illegally signed Betts 18 months prior to him departing Carlton. Adelaide categorically denied the claim, as did Carlton and Betts' manager. Betts and all other parties were subsequently cleared of any wrongdoing in the affair. Following on from this controversy, Betts improved on his stellar 2014 season by kicking 63 goals in 2015, finishing third in the
Coleman Medal, and finally achieving
All-Australian honours. In a
Showdown in round 3, 2017, Betts was racially abused by a club member. The offender was evicted from the ground and had his membership suspended indefinitely. In the Crows' next match, Betts was given the honour of tossing the coin before the match along with player
Anthony McDonald-Tipungwuti before kicking 6 goals, taking the lead in the
Coleman Medal in the Crows' 65-point win. This included 5 first-half goals, and he and McDonald-Tipungwuti kicked 10 goals between them for the match. In round 7, he kicked his 500th career goal against in the second quarter, before being flattened by defender
Scott Thompson and immediately getting a set shot to kick his second goal in a row. Overall he got three goals for the match in spite of the Crows losing by 59 points. Betts had another good performance in 2017's Sir
Douglas Nicholls Indigenous Round, kicking three goals in the Crows' 100-point win over . In August 2017, Betts was admitted to hospital with appendicitis and missed
Adelaide's round 19 draw against
Collingwood but returned the following week for the Showdown and kicked 4 goals, pushing up to second place on the overall Showdown leading goal-kickers list, only behind captain
Taylor Walker. Betts was a part of Adelaide's losing Grand Final team that year, kicking one goal in the match. In 2018, Betts kicked only 29 goals for the year, making it his worst return in 5 years at the Crows. Also in 2018, Betts missed four matches due to hamstring injuries, having missed only one match in his previous four seasons at Adelaide. On Round 5 of the 2019 season, he played in his 300th AFL game, against the
Gold Coast Suns. In front of a roaring crowd and with 6 minutes left in what turned out to be an easy win, he scored a classic left-footed banana that won him an unparalleled 4th AFL Goal of the Year award.
Return to Carlton: 2020–2021 At the conclusion of the
2019 season, Betts was traded back to Carlton. On 19 November 2019, Betts was given his previous jumper number at Carlton, no. 19, once again. On 16 August 2021, Betts announced via Instagram he would be playing his 350th and final AFL match against on 21 August 2021. Betts was chaired off the ground following the match. == Coaching career ==