Originally from Diamond Creek, Victoria, Coventry played his early football for the Diamond Creek Football Club in the Heidelberg District Football League (HDFL). He debuted for Collingwood in 1920, and was joined by his brother, Syd Coventry, at the club two years later. Playing almost exclusively at full-forward, Coventry first led Collingwood's goalkicking in 1922, and would go on to lead the club's goalkicking for 16 consecutive seasons, until his retirement in 1937. He also led the VFL's goalkicking on six occasions: each year from 1926 to 1930, and then again in his final season. In 1929, Coventry kicked 124 goals for the season, becoming the first player in the league to kick over 100 goals in a season, a feat which he would replicate in 1930, 1933, and 1934. Considered the leading forward in the competition in the late 1920s and early 1930s, Coventry played a key part in Collingwood's four consecutive premierships from 1927 to 1930, each captained by his brother. He also went on to win the Copeland Trophy as Collingwood's best and fairest player in 1933. At his retirement at the end of the 1937 season, Coventry held the records for the most career games played and the most career goals kicked, finishing with 1299 goals from 306 games, and thus also becoming the first player to play 300 games. An inaugural inductee into the Australian Football Hall of Fame, and a member of Collingwood's Team of the Century, his career goalkicking record was not broken until 1999, when it was surpassed by Tony Lockett.
He played his early football for Diamond Creek Football Club in the Heidelberg District Football League as well as working for his father's orchard. While playing in the local league he established himself as a champion centre-half-forward before being asked to train at Collingwood by club officials in 1920.
Later that year, Coventry was selected to play his first senior game for Collingwood against St Kilda. He did not make an immediate impact and at times looked clumsy, but did enough to ensure he kept his spot after two valuable seasons. His brother, Syd Coventry was also be welcomed at the club, in 1922. Gordon had kicked 32 goals in those first two seasons, but played in his prime position in the losing grand final side of 1920 where he kicked more than half of Collingwood's score. In 1922 Coventry moved closer to goals and as the team continued its dominance, Coventry became a focal point, and in 1923 would win the club's goal kicking with 42 goals. Coventry did not possess the phenomenal skills of his predecessor Dick Lee or the aerial prowess of his successor Ron Todd, but relied on tremendous strength and a vice-like grip when marking the ball, a combination that made him almost unstoppable once he had front position. By 1923 Coventry was one of the most consistent full forwards in the league and would remain the club's leading goal kicker for the next five seasons, as well as playing in three losing grand final sides. In 1926 he would win his first league leading goal kicking title with 83 goals. When his brother became captain of the side in 1927, success came to the club in more ways than ever achieved. Coventry played in the four consecutive premierships between 1927 and 1930, and in the same years would continue his league dominance, being the finest goal kicker in the league. In the 1928 Grand Final he kicked 9 goals, a league record, and in 1929 he became the first player to kick 100 goals in a season, where he kicked 124 goals, a feat he followed up in 1930 with 118 which included a personal best bag of 17 goals against Fitzroy. Coventry would continue being Collingwood's leading goal kicker during the years 1931–1934, and would win his first and only, Copeland Trophy in 1933, where he kicked another 108 goals for the season.
In 1935 Coventry played in his fifth premiership, kicking four goals to get his side across the line. He would, however, miss the 1936 VFL Grand Final due to suspension, where he was found guilty of striking Richmond defender Joe Murdoch. Coventry played the match against the Tigers with a crop of painful boils on his neck, and when Murdoch repeatedly struck his neck, Coventry retaliated and was subsequently suspended for eight matches. It was his first report in 280 appearances for the Magpies. Nevertheless, Collingwood went on to win the premiership without their champion full forward. Coventry retired after the 1937 season, winning his sixth league leading goal kicker award, and his 16th consecutive club leading goal kicker award. Coventry also represented Victoria on 25 occasions for a total of 100 goals.
After leaving Collingwood, Coventry coached Collegians in the VAFA for a number of years. Coventry kicked 1299 goals in VFL football, a record that stood for more than six decades. He was also the first player to play 300 VFL/AFL games.
In 1996, Coventry was an inaugural inductee of the Australian Football Hall of Fame and was elevated to "Legend" status two years later. In 1998 he was named at full forward in Collingwood's team of the century. The Gordon Coventry Trophy is awarded to Collingwood's leading goal kicker each year. The southern end of the Docklands Stadium is named the "Coventry end". When the Southern Stand at the MCG was built, a gate/entrance was jointly named after Coventry and brother Syd. In 2009, The Australian nominated Coventry as one of the 25 greatest footballers never to win a Brownlow Medal.
Coventry died in 1968 of heart disease at his property in Diamond Creek, survived by his wife and four children.