Born in
Otley,
West Yorkshire, England, Kernaghan moved with his family to Bangor, County Down at the age of four. He represented
Northern Ireland at schoolboy level and the
Republic of Ireland at senior level. He began his playing career as an apprentice at
Middlesbrough, and went on to make 212 appearances during an eight-year period, scoring 16 goals. In September 1993, Kernaghan was signed for
Manchester City by then-boss
Brian Horton. He went on loan to various clubs—
Bolton Wanderers in 1994,
Bradford City in 1996, and then to
St Johnstone in 1997. The Saints signed him on a permanent deal just before the end of the year, after he was given a free transfer from Manchester City. He enjoyed four years at
McDiarmid Park, making 60 league appearances and scoring five goals. Kernaghan then joined
Brechin City, but he made only three competitive appearances for the club. He then moved to
Clyde, where he started as a player but was promoted to a player/manager role in the 2003–04 season. He guided Clyde to a second-placed finish in the
First Division, behind
Inverness Caley Thistle, a division which they led for the majority of the season. Kernaghan made 63 appearances for Clyde as a player, scoring three goals. Kernaghan's next move was to
Livingston as assistant manager to
Allan Preston. Kernaghan next moved to
Falkirk, where he took up a player/coach role. ==Coaching career==