Sheffield born Barwick came through the youth ranks of Scunthorpe United and was added to the first team squad in the final months of the 1999–2000 campaign.
[3] Despite joining The Mariners on a two-year deal and having arrived with praise from his former management staff at Scunthorpe, Barwick struggled to find his feet at Blundell Park and found himself looked over in favour of players such as Paul Bolland, Ciaran Toner and Jean-Paul Kamudimba Kalala.
The Mariners started the 2006–07 season under different command, when Russell Slade left the club, and in stepped his assistant Graham Rodger.
It wasn't long before he was allowed to leave the club, and his two-year contract was cancelled when he signed for Northwich Victoria a couple of weeks into the new season in August.
[6][7] He made a permanent move to the Conference when he joined Northwich Victoria in August 2006 and finished the 2006–07 season with 21 appearances.
[8] Barwick was released by Celtic after the conclusion of the 2008–09 season, and signed for Northern Premier League side Retford United.