Born in Ballymun, but growing up in Glasnevin, Dublin, Rock attended St Kevins College, Ballygall.
[2] He played Gaelic football with his local club Ballymun Kickhams and was a senior member of the Dublin county team from 1980 until 1991.
[3] He won the 1983 All-Ireland Senior Football Championship with Dublin in 1983 at Croke Park against Galway.
[5] Rock was an unsuccessful candidate at the 1991 Dublin Corporation election for the Progressive Democrats.
He stood for election to the local electoral area of Finglas on Dublin Corporation.