He played 33 games with Footscray in the Victorian Football League (VFL) from 1967 until 1969 but it was in the Victorian Football Association (VFA) with Yarraville and Port Melbourne that he made his name. In his brief career with Footscray he played in defence and only kicked two goals; at Yarraville, he won the J. J. Liston Trophy playing as a ruckman and defender; then with Port Melbourne, he became one of the Association's premier forwards, leading the VFA goalkicking in five separate seasons and kicking all-time VFA career record of 1364 goals from his 305 games.
Cook grew up in Yarraville in Melbourne's inner western suburbs, and supported Footscray in the VFL. He played amateur football as a junior for the Footscray Tech Old Boys, then joined the Footscray Football Club in 1967 at age 19. In his second season, 1968, Cook played every game, primarily at centre half-back, and was already developing a reputation as one of the strongest marks in the league.
After the sixth round of the 1969 season, Cook was dropped from Footscray senior side to the reserves, along with six other players, as a disciplinary action for attending a family BBQ at former coach Charlie Sutton's house, which club secretary Jack Collins had thought would be a drunken swill, and had discouraged players from attending. After two weeks in the reserves, Cook was encouraged to crossover to Yarraville in the VFA. The VFA had recently broken its permit agreement with the VFL, meaning that Cook did not require a clearance from Footscray to make the move; and, because the VFA lacked the restrictive player payments laws that the VFL had, Yarraville could offer Cook more money than he was then making at Footscray. In 1970, his first full season with Yarraville, he won the J. J. Liston Trophy for the VFA's best and fairest player playing as its first choice ruckman. Despite his efforts, Yarraville won only one game for the season and was relegated to Division 2, and Cook decided to transfer to Port Melbourne in 1971, where he continued as either a center half-back or a center half-forward, depending on the opposition line up.
During a 1972 pre-season practice match against Brunswick, Cook suffered a heart attack between the first and second quarters, but he managed to play the game out and still take 17 marks. He spent the next three weeks in hospital and was advised to retire from football. But, Cook was determined to play again, and made a return later that year. In his first reserves game after the heart attack, he was played at full-forward to keep him out of the heavier action, and he kicked sixteen goals. He made his return to senior football in the last game of the year, less than six months after his heart attack.
Cook was still a utility player at Port Melbourne, playing in the half-backline, ruck and forward-line depending on the needs of the team until 1974 – and in fact, in mid-1974, five years into his VFA career, he was still described as "a makeshift full-forward" by sportswriters of the time. He went on to kick 10.2 from his twelve kicks in that year's Grand Final, and thereafter he was a permanent full forward, and he dominated the Association's goalkicking for the next decade. He topped the VFA's goalkicking five times in a prolific period from 1976–1982. His highest tally was in 1977 when, in an extended 26-match season, he kicked 167 goals: 125 in twenty premiership matches, 30 in four matches of the once-off Centenary Cup competition, and 12 in two matches of the NFL's Ardath Cup Night Series. He played in all six of Port Melbourne's premierships, plus the Centenary Cup victory, during the 1974–1982 period, and was a noted performer in Grand Finals, kicking 10 goals in the 1974 Grand Final, 12 goals in the Centenary Cup Grand Final, 9 goals in the 1977 Grand Final, and five goals in the infamous 1976 Grand Final, despite having been king-hit in the second quarter. He represented the VFA in interleague competition on nine occasions, including several times as captain.
He announced his retirement from Port Melbourne at the age of 36, shortly before the end of the 1984 season, having played 258 games and kicked 1238 goals for the club over 14 years; although he had little say in the matter, as club officials indicated that he would no longer be selected in the team due to diminishing returns over his final two seasons. He made a comeback for Division 2 club Moorabbin in 1985, playing eighteen games to become the first player to play three hundred VFA games, before retiring permanently from the VFA.
Cook now holds the record for most goals kicked in the VFA, at 1364, and is one of only five players to have scored 1400 or more goals in his career at top-level senior and representative football. Cook's success was largely attributed to his marking: he was widely regarded as being one of the strongest and safest marks in the game, even in his early years at Footscray. Through the peak of his career, he was also one of the game's fastest sprinters over a short distance, giving him an advantage as a leading forward. However, somewhat ironically for the VFA's all-time leading goalkicker, he was a poor kick for goal, and many observers commented that he could have kicked many more goals, and perhaps even have become the first man to kick 200 goals in a season, if he'd been a more accurate goalkicker; but, his marking was so dominant and generated so many set shots from close range that it made up for his inaccuracy.
In 2014, the Lorimer St end of North Port Oval was renamed the Cook End in honour of Cook's goalkicking achievements for Port Melbourne.
Throughout the 1970s, Cook became the most well known and popular player in the VFA. His status as a marketable and likeable celebrity contributed significantly to the popularity of the VFA during that time, and he took on several media commitments, including a VFA column in the Sporting Globe newspaper and a segment on the World of Sport television program. He spoke regularly at sportsman's nights, and had a promotions job with Puma SE. From 1982 until 1985, Cook was the publican of the Station Hotel in Port Melbourne, and his celebrity status helped to make the pub successful during that time.
While at the Station Hotel, Cook came to associate with criminal Dennis Allen, and began to use amphetamines. After 1985, Cook became addicted to the drug, which brought him close to being broke, and he later began to deal. He served three jail terms between 1990 and 1997 on drugs-related offences.