Shannon first played hurling to a high standard as a student at O'Connell School and lined out in the Leinster Colleges SHC.
At club level, he played with Scoil Uí Chonaill and was part of the team that won the Dublin JHC title in 1958, before claiming the Dublin IHC in 1959.
Shannon made his senior team debut in the Walsh Cup in 1958.
He won a Leinster SHC medal in 1961 following Dublin's first provincial success in nine years..[3] Shannon was at wing-forward when Dublin were beaten by Tipperary in the 1961 All-Ireland final.
He won a Railway Cup medal in 1962 following Leinster's 1-11 to 1-09 defeat of Munster in the final.