At inter-county level, Sherlock was part of the successful Cork under-21 team that won back-to-back All-Ireland Championships in 1997 and 1998. He joined the Cork senior team in 1999. From his debut, Sherlock was ever-present as a defender and made a combined total of 66 National League and Championship appearances in a career that ended with his last game in 2007. During that time he was part of three All-Ireland Championship-winning teams – in 1999, 2004 and 2005. He also secured five Munster Championship medals and captained the team during the 2002 season. A groin injury lead to Sherlock losing his place on the starting fifteen towards the end of his career and he announced that he was leaving inter-county hurling on 30 March 2007.