Lockett began playing Australian Rules with the Under 12s team of his father's club, North Ballarat Football Club, in 1974. He played a total of 120 junior games with the club. He had played just five senior games as a 16-year-old in 1982 with North Ballarat before he was recruited by VFL club St Kilda and moved to Melbourne.
In Lockett's second year with the club, he kicked seven goals in the opening game against the Essendon Football Club and then went on to kick 70 more goals to win St Kilda's leading goal kicker award. In 1987 he won the Brownlow Medal. His best season at St Kilda was in 1991, when he kicked 127 goals in 17 games, at an average of 7.47 goals per game, the second highest average ever achieved in VFL/AFL history (after Peter Hudson's 1972 and 1973 averages of eight after playing only one game each year). He was also the spearhead for St Kilda's first finals appearance since 1973. In 1992 he kicked the most goals that season with 132 goals. In a qualifying final against Geelong he kicked nine goals and five behinds, although the Saints were beaten by seven points. He was described by dual Brownlow medallist Robert Harvey as the best player he had ever seen.
In 1995, Lockett transferred to the Sydney Swans, where he played for another six seasons. He was an instant success with the Swans, helping the team into the 1996 finals series and subsequently into the 1996 AFL Grand Final. With scores tied in the preliminary final game, Lockett kicked a point after the siren to give Sydney a one-point victory. Despite a groin injury he played in the grand final, which the Swans lost to North Melbourne. It was the only grand final appearance of Lockett's career.
Lockett's career-best goal-scoring performance came in Round 19, 1995, against Fitzroy at the Western Oval, when he scored 16 goals straight.
Lockett became a cult figure in Sydney. He was a massive drawcard for the struggling Sydney Swans, who had previously found it difficult to attract large support in New South Wales's rugby league heartland. At the height of his popularity the song "There's only one Tony Lockett" was released (sung to the tune of "Guantanamera"), performed by James Freud.
In 1996, Lockett was the subject of much hype in the clash between Geelong and Sydney in which Gary Ablett Sr. was playing at the other end of the ground. The match was billed by the media as Plugger vs God and set a ground record attendance at the Sydney Cricket Ground. He broke the record of 1299 career goals (set by Gordon Coventry) at the SCG in 1999 and sparked one of the biggest pitch invasions seen in Australian rules football.
Lockett retired at the end of 1999 but had a brief comeback in 2002, playing three games and adding three goals to his record.
Lockett's career was marred by several high profile tribunal appearances. The most famous was in an 11-goal match for St Kilda, against his future club, Sydney, in 1994 when he broke Peter Caven's cheek-bone as he led out from full-forward and the unaware Caven was back-tracking for the ball. The incident resulted in an eight-week suspension for charging.
Lockett's aversion of the media has been well documented. Since his retirement he has been elusive and has had little involvement in the game.
He has appeared in various television commercials, including Advanced Hair and Lowes Menswear (in Sydney). While at a taping session for a Lowes commercial, Lockett engaged in a friendly wrestling match with former amateur rugby player Ace (Adrian) Mueller, who was at the time working for Lowes corporate division. According to some reports, the friendly wrestle developed into something quite competitive, with Lockett pinning Mueller (an exponent of the Israeli self-defence system, Krav Maga). More recently Tony starred along with Stephen Curry and Dave Lawson in a Toyota Memorable Moments advertisement which takes a lighthearted look at many moments in his career including: the piglet 'Pluga', 'One Tony Lockett', 'That Point' and his 1,300th goal (including the pitch invasion).
Lockett's father, Howard, inherited the nickname "Plugger" from his own father who used to "plug around" in the garden. Howard Lockett, who himself played 500 games of country football, then saw it fit to pass down the nickname once more to his son and it became synonymous with his large size.
In Round 18, 1993, in a match at the Sydney Cricket Ground between St Kilda (then Lockett's club) and Sydney (his future club) a piglet (being a reference to Lockett's build) was released by a member of the Sydney crowd onto the ground (with the wrongly spelled word "Pluga" and Lockett's playing number of "4" spray painted onto it) before being tackled to the ground and removed by Sydney Swans player Darren Holmes. The Channel Seven commentary of the incident had the exclamation of "There's a pig at full-forward!" from commentator Sandy Roberts. Lockett was actually absent from the match due to injury.
On 19 July 2009 he was inducted into the Sydney Swans Hall of Fame.
In 2003 he was inducted into the St Kilda Football Club Hall of Fame and on 24 July 2010 he was elevated to "Legend" status.
Lockett kicked over one hundred goals in a season on six occasions - at St Kilda in years 1987 (117); 1991 (127); 1992 (132) and at Sydney in years 1995 (110); 1996 (121) and 1998 (109). This is a league record for the number of times a player has kicked over 100 goals in a separate season, which he shares with Jason Dunstall.
The New South Wales Primary Schools Sports Association Australian Football competition is named the Tony Lockett Shield.
Victoria 19.12 (126) defeated Western Australia 10.12 (72), at the WACA Ground, 16 May 1989, crowd: 20,993 Victoria 22.17 (149) defeated South Australia 9.9 (63), at the MCG, 1 July 1989, crowd: 91,960