Born in Ballylongford, County Kerry, Walsh was born into a strong Gaelic football family. His father, Johnny Walsh, was a five-time All-Ireland medal winner with Kerry between 1932 and 1941. Walsh's brother, Barry, also played with Kerry.
Walsh first came to prominence on the inter-county scene as a member of the Kerry under-21 team. He was captain of the team in 1972 and won a Munster medal before later ending up as an All-Ireland runner-up. By this stage he had also joined the Kerry senior team, making his debut during the 1970-71 league. Over the course of the next twelve seasons Walsh was a regular member of the panel at various times and won two All-Ireland medals in 1975 and 1980. He also won four Munster medals and four National Football League medals.