After signing a reserves contract and featuring in six reserves games for Hawthorn, Ablett retreated back to his home in Drouin. He returned to Hawthorn in 1982 and made his senior VFL debut versus Geelong in Round 2, kicking 1 goal and helping the Hawks defeat the Cats by 19 points. He played a further five games for Hawthorn that year for a total of six games and ten goals. Ablett claimed difficulty coping with city life in Melbourne and his continual absenteeism from training sessions forced Hawthorn coach, Allan Jeans into parting ways with the talented, but wayward young half forward.

In 1983, he moved with his young family to the country town of Myrtleford. Ablett spent the year playing under the tutelage of his cousin Len Ablett for Myrtleford in the Ovens and Murray Football League. Ablett’s footballing ability soon came on notice again, this time to the Geelong Football Club and their long-time recruiting officer Bill McMaster. McMaster convinced Ablett to give the game another shot, this time in the confines of the rural city of Geelong. After protracted negotiations with Hawthorn, Geelong finally paid a $60,000 transfer for Ablett in 1984.

Ablett signed a one-year contract for the 1984 season with Geelong, and he began his first season under the guidance of Tom Hafey. He debuted for the Cats in Round 7 and after just nine games on the wing, Ablett was selected to his first State of Origin game for Victoria. Ablett earned best-on-ground honours after kicking 8 goals from the half-forward flank. He played 15 games and kicked 33 goals in the 1984 season, and was awarded the Carji Greeves Medal as the Geelong Football Club’s “best and fairest” player of the year. Following his first season with Geelong, Ablett signed a new three-year contract with the club.

Ablett had a prolific State of Origin career, kicking 43 goals in 11 games. He was first selected to play for Victoria in 1984, against Western Australia, only nine games into his career at Geelong, kicking 8 goals in a best-on-ground performance.

The youngest of eight children, Ablett grew up alongside four elder brothers and three elder sisters. In 1985, Ablett wed his long-time girlfriend Sue, and the couple had four children – Natasha, Gary Jr., Nathan, and Alisha.

In 1986, Ablett became a born-again Christian and has been said to be slightly aggrieved at constantly being referred to as “God” by fans, a nickname based on his supreme football abilities. Ablett’s faith was often highlighted in several tribunal appearances, in one case confessing and pleading guilty to striking Garry Lyon in a 1989 incident, declaring he “wasn’t prepared to lie about it or compromise the truth in [his] relationship with God”. Ablett’s public acknowledgement of his faith, in particular the influence of God in his life, during his acceptance speech for the Norm Smith Medal in the 1989 Grand Final, was also much publicised.

The 1989 season was marked by the arrival of Ablett’s third coach, former North Melbourne Brownlow Medallist Malcolm Blight. Ablett helped the Cats reach the finals on the back of a ten match winning streak to end the regular season. In a 134-point victory against Richmond, Ablett scored 14 goals, breaking a 22-year club record, and moving club legend and former club premiership coach Bobby Davis to laud Ablett as the equal of the legendary Graham ‘Polly’ Farmer, the finest footballers he had seen at Geelong. His season lowlight occurred in Round 12 when he was suspended for 3 matches after he controversially felled the Melbourne captain, Gary Lyon behind the play.

Against the reigning premiers Hawthorn in the 1989 VFL Grand Final, Ablett asserted himself from the opening bounce, leading out from full forward, marking the first centre clearance kick and slotting through the game’s first goal. By half-time, Ablett had kicked four goals, but the Cats trailed at the main break by 37 points. Ablett kicked a further five goals in the second half, which saw an injury-depleted Hawthorn’s lead reduced to just 6 points with less than a minute to go. However, the Cats fell short, and Hawthorn held on to defeat Geelong in one of the toughest grand finals of the modern era, winning by 6 points. Ablett’s performance in kicking 9 goals earned him the Norm Smith Medal, and in doing so became only the second member of the losing team in VFL/AFL history to be awarded the honour – a performance regarded by many as unrivalled on football’s biggest stage. Ablett’s 9 goals also saw him equal Gordon Coventry’s goals record set in the 1928 Grand Final.

Ablett combined strength, speed, and skill to produce many spectacular highlights and goal-kicking feats. A noted big game player, Ablett kicked 43 goals in 11 State appearances. More significantly, he booted 64 goals over the course of his 16 finals – an average of four goals a game. His haul of 27 goals in the 1989 finals series is a record that still stands. He was awarded the Norm Smith Medal for his performance in the 1989 Grand Final, where he was adjudged best player afield. In doing so, he became one of only four players (the others being Maurice Rioli −1982, Nathan Buckley −2002, and Chris Judd −2005) to win the medal playing for the losing side. In 1996, Ablett joined Gordon Coventry, Doug Wade, Jason Dunstall and Tony Lockett as the only players in league history to kick 1000 VFL/AFL goals.

He performed well again the following year, kicking 4 goals against South Australia. In the following few years Ablett was largely out of the side, apart from 1987, when he kicked 2 goals against South Australia. Ablett again performed at the highest level in 1990, kicking 6 goals, against Western Australia in Perth. After returning from retirement midway through 1991, and after only several games, Ablett was controversially selected for Victoria, kicking 2 goals. In 1992 Ablett performed well, kicking 3 goals and being named among the best players, against Western Australia.

Ablett had well-documented off-field problems, particularly with illegal drug use, and depression in the wake of the Alicia Horan death. In 1990, Ablett was placed on a $10,000 good behaviour bond after he pleaded guilty to repeatedly hitting a man he found sitting in a car with his estranged wife.

On 1 February 1991, Ablett, aged 29, stunned most football fans when he announced his retirement, citing personal reasons and a loss of enjoyment for the game. His previous season in 1990 was marred by injury, dipping motivation, and personal issues, including a separation from his wife. He was eventually encouraged to reverse his decision and he made his return in Round 12 for the Geelong reserves team. This generated enormous media interest and drew an abnormally large crowd for the curtain-raiser game at Princes Park. Ablett was slotted back into the senior side in Round 13. He failed to recapture his best form, however, and he kicked just 28 goals throughout 12 appearances. His year ended on a sour note when he was suspended for striking St Kilda rover Nathan Burke in the first week of the finals, and he subsequently missed Geelong’s finals defeats to Hawthorn and West Coast.

Before the 1993 season, Ablett was encouraged by his coach, Malcolm Blight, to move from his customary roaming half-forward position to full-forward, in an effort to prolong his career. The move up forward proved to be a master-stroke, with Ablett thriving in his goal-kicking role, reaching the 50-goal mark in just six games, equalling the sixty-year record of South Melbourne legend Bob Pratt. He brought up his maiden century of goals in the season just eight games later, one game slower than record-holder Pratt, and became the first Geelong player to kick 100 goals in a season since Larry Donohue in 1976. Although the Cats did not make the Finals, Ablett’s new-found dominance up forward was highlighted during the season with his bags of ten or more goals on five occasions, including a 14-goal performance against Essendon in Round 6. His end-of-season total of 124 goals, achieved in just 17 appearances, earned him his first Coleman Medal as the League’s leading goal-scorer, the Leigh Matthews Trophy, the AFMA Player of the Year Award, and a top-ten placing in the Brownlow Medal.

In 1993, he kicked 4 goals, against a combined New South Wales–Australian Capital Territory side, and in the same year Ablett again performed on the big stage, kicking 5 goals in the State of Origin Carnival Grand Final. In 1994, he kicked 4 goals, against South Australia, in what has been regarded as “one of the greatest Australian football games of all time” and followed up that performance with 4 goals against South Australia in 1995. On representing Victoria, Ablett has said “I’ve always found it a tremendous honour to represent your state, in a State of Origin game”.

Ablett continued his dominance as a full-forward in 1994 and 1995 by winning the Coleman Medal in each year. Ablett is the only player in VFL/AFL history to kick 100 goals and win the Coleman Medal in three successive seasons. In addition to his explosive pace and skills, Ablett was also an accomplished aerialist with strong hands. A highlight was the 1994 Mark of the Year over Collingwood’s Gary Pert on Mother’s Day at the MCG, a mark which is captured in Jamie Cooper’s painting the Game That Made Australia, commissioned by the AFL in 2008 to celebrate the 150th anniversary of the sport. There is still debate over whether he had enough control of the ball to be paid a mark.

In early 1996, Ablett was suspended for five games for striking St Kilda’s 172 cm Kristian Bardsley with a raised forearm. He later remarked that his lengthy suspension was the “beginning of the end”, and he finished out the season with 69 goals in 17 games. His last AFL appearance was against North Melbourne in a Qualifying Final in 1996. Ablett managed to kick only one goal in a disappointing 60-point loss. In October 1996, he missed Geelong’s first training session and was fined $10,000.

On 22 November 1996, Ablett was admitted to hospital with a severe bout of gastro. On 28 November, Ablett faced traffic charges.

Martin Flanagan’s representation of Australian football pioneer Tom Wills in his 1996 novel The Call is modeled on Ablett. According to Flanagan, Wills and Ablett polarised opinion in similar ways, and displayed a lack of insight into their actions—they simply did what came naturally to them, “like a lot of artists”. Ablett is the subject of the song “Kicking the Footy with God”, released by The Bedroom Philosopher on his 2005 debut album In Bed with My Doona.

In 1996, Ablett was named in the AFL Team of the Century on the interchange bench, alongside Jack Dyer and Greg Williams. In 2001, Ablett was named in the Geelong Team of the Century, on a half forward flank. In 2005, after many years of controversy and debate (see below), he was inducted into the Australian Football Hall of Fame. The following year, he was honoured yet again when he was voted as the Greatest Geelong player of all-time ahead of Graham Farmer.

Ablett was ready to start the serious training with the club by the first week of January. By February, it was reported that he was still under pressure to improve his fitness. In March, Geelong confirmed that Ablett would play in 1997. On Sunday, 31 March 1997, Ablett played in the reserves against Richmond. Gary booted 7 goals but injured his knee. Three days later, on 3 April, he underwent arthroscopic surgery. In early June, Ablett had still not recovered; he faced knee surgery. During the preliminary finals in September, he announced his retirement from football.

In 2000, Ablett was investigated, charged and convicted of four drug offences as a result of nineteen-year-old Geelong woman Alicia Horan dying of a drug overdose (involving heroin, ecstasy and amphetamines) while in Ablett’s hotel room. After a prolonged period of refusing to answer police questions – with Ablett stating he had “received pressure from certain avenues not to give all the facts” – he admitted to providing Horan with heroin and other drugs, which he took with her. Ablett pleaded guilty to all four charges, was convicted, and fined $1500.

Despite his footballing achievements on the field, Ablett’s induction into the Australian Football Hall of Fame was initially delayed. Despite Ablett’s undoubted footballing credentials, his well-publicised contribution to the death of Alicia Horan was responsible for the Australian Football Hall of Fame committee’s reluctance to induct him. In 2004, after several years of speculation over his induction, Ablett personally requested that the Geelong Football Club stop nominating him for selection, which the club agreed to. However, the following year it was announced that Ablett would be inducted into the Hall of Fame as part of the 2005 intake.

In addition to his sons, Ablett has a nephew, Luke Ablett, who played for the Sydney Swans and won a premiership with them in 2005. Two other nephews, from his sister’s marriage to Hawthorn legend Michael Tuck, also played in the AFL – Richmond’s Shane Tuck and Travis Tuck, who played for Hawthorn.

In 2006, Ablett was honoured with the naming of a terrace in his name within the newly renovated Skilled Stadium. Ablett once had a set of gates named in his honour, but he was upgraded to a terrace at the beginning of the 2006 AFL season.

On 26 June 2006, Ablett was allegedly assaulted at 11:15pm while browsing through a car yard in Fyans Street, South Geelong. A 31-year-old Geelong man was charged with the assault. However, he was reported to have committed suicide on 10 July 2006 by jumping from a Melbourne high-rise apartment block the day before he was due to appear before the Geelong Magistrates court to defend the assault charges.

In December 2007, Ablett hit back at media claims that his son Nathan had walked away from his football career because of the publicity surrounding the release of a new book about his father. Although normally reluctant to make public comments, Ablett felt that the media intrusion into his family life had gone too far. As part of a series of books, “Legends of Australian Sport”, Ablett contributed to a book regarding himself. It was the first time he revealed intimate details regarding his life publicly.

Ablett’s eldest son, Gary Jr., has followed in his footsteps to play for Geelong. In 2007 and 2009, Ablett Jr. won the Cats’ best and fairest award, emulating a feat established by his father in his first season with the Cats back in 1984; he also won the Brownlow Medal in 2009 and 2013. Another son, Nathan, was drafted in 2004 (48th pick) by Geelong under the father-son rule. Nathan initially refused to play AFL Football because of his father’s experience with the media, but, with encouragement from the club, was signed ahead of the 2005 AFL Season and established himself in the full forward role Gary Sr. made his own.

On 29 September 2007, both Gary Jr. and Nathan contributed to Geelong winning its first flag in 44 years, capturing the premiership that proved elusive to Gary Snr in his 12 years at the club. Nathan retired suddenly before the 2008 season, but he and his brother Gary Jr. were members of the Gold Coast Football Club’s inaugural team for the 2011 season.

In September 2020, Ablett released a 27-minute YouTube video discussing his belief in the rapture as being forthcoming. In this video, he declared that the COVID-19 pandemic had been manufactured and released by the Illuminati and Freemasons in order to depopulate Earth, create a cashless society and “put Lucifer on the throne of the world”.