McKay grew up in south eastern South Australia, and played junior football for Lucindale in the
Kowree Naracoorte Football League. Recruited by
South Australian National Football League (SANFL) club
Glenelg, McKay moved to Adelaide in 1991 and played 40 games for Glenelg as a half-back flanker, finishing second in the
Magarey Medal in 1992 behind
Port Adelaide's
Nathan Buckley.
Carlton McKay was recruited by
Carlton Football Club with its first round selection in the
1992 AFL draft (No. 13 overall), although he was later fined $10,000 when it emerged that he had contacted four of the AFL's struggling clubs (, , and ) and warned them that he would stay in South Australia if one of those clubs drafted him – which contravened the AFL's draft tampering rules. He nevertheless remained eligible to play for Carlton, and he made his debut in Round 1,
1993, immediately displaying the outstanding defensive skills that he had displayed at Glenelg. In his first AFL season, McKay was named on the half-back flank in the
All-Australian team. He also represented
South Australia at State of Origin that season, a feat he repeated in
1994 and
1995. In 1995, McKay was a member of
Carlton's premiership team, the only premiership in his senior career. McKay played 15 of Carlton's 24 matches in the
1996 AFL season. Continuing with Carlton, McKay played two more matches for South Australia, and was the winner of the
Fos Williams Medal before the end of top-level State of Origin football in 1999. He made the All-Australian team as half-back flanker three times consecutively in
1999,
2000 and
2001, bringing his career tally to four. In
2003, McKay's final season, he assumed the Carlton captaincy following the mid-season retirement of
Brett Ratten, and also won Carlton's
Best and Fairest award for the only time in his career and McKay announced his retirement from his playing career at the end of the 2003 season. McKay played a total of 244 games and kicked a total of 28 goals for
Carlton Football Club from 1993 until 2003. He was also member of Carlton's
1995 premiership team. McKay is a life member and Hall of Fame Inductee of the Carlton Football Club. In 2007, he was inducted into the
South Australian Football Hall of Fame. ==Sports administration career==