Stephen Kernahan is the son of Glenelg footballer, general manager and legend Harry Kernahan, and the older brother of former Glenelg and Carlton player David Kernahan. He began his senior career with Glenelg in the South Australian National Football League (SANFL) in 1981 and played 136 games, kicking 290 goals, winning 3 straight best and fairest awards. Under the coaching of 1961 Magarey MedallistJohn Halbert, Kernahan was a member of Glenelg's losing Grand Final teams to Port Adelaide in 1981 and Norwood in 1982.
In 1983 he topped the voting in the Magarey Medal with a then record 44 votes, made all the more remarkable as Glenelg only won 9 of 22 games for the season (after losing their first 8 games), half the number won by premiers West Adelaide. Unfortunately he was ineligible due to being reported for an incident with Norwood'sGarry McIntosh in Round 4 and was suspended for Round 5. Due to the rules of the SANFL, any player who receives a suspension during a season is ineligible to win the Medal and the award was won by North Adelaide'sTony Antrobus who polled 35 votes. Kernahan was also twice leading goal kicker for The Bays, in 1983 and 1984 and in 1985 he was awarded the Jack Oatey Medal as best on ground in the club's premiership win over North Adelaide.
In his days with Glenelg, Kernahan was mostly used as a ruckman / forward due to his 6'5" (196 cm) height and his strong marking and leading ability. He played mostly at Full-forward and was the Tigers second ruckman behind Bays legend Peter Carey. This would lead him to being Glenelg's leading goal kicker in both 1983 and 1984. His height and his slight build led to the nickname "Sticks".
Kernahan was signed by Carlton in the Victorian Football League (VFL) in 1981, but he didn't move to the club until 1986 due to his ambition to play in a premiership with his best mates at Glenelg. The anticipation of Kernahan's arrival was heightened when he played State of Origin games for South Australia and his outstanding play, usually at full-forward, saw those in Victoria take notice. In 1983, Kernahan was a member of the South Australian side which defeated Victoria in Adelaide for the first time in 18 years. He kicked 10 goals in a losing side against Victoria at Football Park in Adelaide in 1984, winning the Fos Williams Medal as South Australia's player of the match. He was a mainstay of the South Australian state of origin teams throughout his careers at Glenelg and Carlton, playing a total of sixteen games for the Croweaters, winning a second Fos Williams Medal in 1988, and captaining the team in 1996.
After winning the 1985 premiership with Glenelg, Kernahan finally moved to Melbourne to join Carlton in 1986, the same year as two other quality South Australian players, Craig Bradley from Port Adelaide and Peter Motley from Sturt joined The Blues and the three were immediately influential for the Blues. Playing primarily at centre half-forward, and sometimes at full-forward throughout his career, Kernahan kicked 62 goals in his first season at Carlton, to be the club's leading goalkicker for the first of a club record eleven consecutive occasions.
In only his second season at the club, Kernahan was made club captain. He became widely regarded for his leadership as captain, with former club chief executive Ian Collins describing him as "on and off the field, the greatest leader [Carlton] has ever had". He held the captaincy for eleven years until his retirement, and his 226 games as captain is a VFL/AFL record for any club. In the final round of the 1987 season, he famously kicked a goal after the final siren to defeat North Melbourne and clinch the minor premiership and the bye in the first week of the finals, and Carlton went on from that position to win the Grand Final against Hawthorn and its 15th premiership. Kernahan won his first of three club best and fairest awards that season.
Over the following few years, Kernahan won another two club best and fairest awards in 1989 and 1992, and continued to win the club goalkicking annually, with his highest total of 83 goals coming in 1992. He was selected in the All-Australian team in 1992 and 1994. He led Carlton to the 1993 Grand Final against Essendon, which the club lost badly despite Kernahan's seven goals. Two years later, Kernahan led the club to the 1995 premiership, kicking five goals in the Grand Final against Geelong.
Kernahan retired at the end of the 1997 season. In that year, he passed Harry Vallence to become the leading career goalkicker in Carlton Football Club history; he finished his VFL/AFL career with 738 goals, which remains a Carlton record as of 2014.
Overall, Kernahan played a total of 403 senior games for Glenelg, Carlton and South Australia, and kicked 1133 goals. He was selected as an All-Australian five times: three times when the team was selected based on interstate carnival performances (1985, 1986 and 1988) and twice when the team was selected based on AFL performances (1992 and 1994). He is a Carlton and AFL life member, and has been inducted into the Australian Football Hall of Fame and the South Australian Football Hall of Fame.
Kernahan is regarded as one of the greatest players in Carlton Football Club history. He was centre half-forward and captain of the club's Team of the Century, he was made a Legend of the Carlton Football Club Hall of Fame in 1997, and as part of the club's sesquicentennial celebrations in 2014 he was named the second-greatest player in the club's history, behind only John Nicholls.
After retiring as a player, Kernahan joined the Carlton Football Club's Board of Directors, and in 2006 became a vice-president of the Club. Following Graham Smorgon's failure to be re-elected at the 2007 Board Elections, Kernahan was made interim president, acquiring the services of and relinquishing the position to Richard Pratt within days. On 20 June 2008 he again took the role of president, this time permanently, after Pratt stood aside to fight charges of giving false and misleading evidence to an Australian Competition and Consumer Commission. Kernahan served as president for six years before stepping aside in June 2014.