While attending Gosford High School, Fairleigh played for the
Australian Schoolboys team in 1988. He made his first grade début for the
Bears in round 17 of 1989 and for ten seasons from 1990 was a permanent first grade player and North Sydney stalwart. During this period he was consistently one of the dominant forwards in the NRL. He made his
State of Origin début in game III of 1991. He was not selected in 1992 but appeared again in 1993 playing in all 3 games for NSW and winning the series. He played State of Origin from 1991 to 1997, playing in 10 games. Although not selected for Origin in 1994, Fairleigh won the
Rothman's Medal in 1994 for the best and fairest player in the NRL with a record tally of 33 votes. Fairleigh made his Test début for
Australian in a
one-off test against
France. At the end of the
1994 NSWRL season, he was one of the first forwards selected for the
1994 Kangaroo Tour. He appeared in twelve minor tour matches and two Tests, scoring five tries on tour. He had been selected for the second Test but withdrew on the morning of the match with a virus. He played in the third Test against Great Britain and in the sole test against France, scoring a try in the 74-0 drubbing. His NSW Origin career spanned from 1991 – 1997. He played in all three games of 1993, 1995, 1997 Origin series and the 3rd game of the 1991 series for a career total of ten appearances for the
Blues. He was also selected in the Australian team to play against Fiji and Papua New Guinea in 1996. In 1996 he was named in the World Team and was named Dally M Second Row of the Year. He was second in the Rothmans Medal in 1996 behind teammate
Jason Taylor. Fairleigh played a total of 193 games for Norths and played in 3 of their 4 preliminary final losses during the 1990s as the club fell agonizingly short of a grand final appearance. Following North's merger with
Manly Warringah Sea Eagles at the end of 1999, Fairleigh moved to Newcastle and was in 2000 named the club's Player of the Year, Players' Player and Coach's Player of the Year. 2001 saw him finish his club career with a season for
St. Helens in England where he was named in the Super League Dream Team as well being chosen as one of St Helens 100 greatest players. The same year he played in the winning St Helens team in the 100th Challenge Cup Final against Bradford Bulls at
Twickenham. As
Super League V champions,
St. Helens played against
2000 NRL Premiers, the
Brisbane Broncos in the
2001 World Club Challenge. Fairleigh played as a prop forward in Saints' victory. ==Post playing==