Des Foley was born into a farming family at Kinsealy, County Dublin in 1940. As a young man he showed particular skill at Gaelic games, winning four Dublin County Senior Hurling Championships with the St Vincents GAA club, having earlier captained the St Joseph's school team which brought the All-Ireland Colleges football title to Dublin for the first time. Foley captained the Dublin minor football team which won the All-Ireland Final in 1958. In 1962 he became the only player in history to play in two provincial Railway Cup finals, in hurling and football, on the same day, winning medals in both codes for Leinster. He won further Railway Cup medals again in 1964 and 1965.
Foley was a prominent member of the Dublin Hurling team from 1958 until 1969, playing on the losing side in the 1961 All-Ireland Final. In 1963 he captained the county football side which defeated Galway to win the All-Ireland title. He won three All-Star awards, two for football and one for hurling, but never a senior All-Ireland hurling medal. He was a mid-fielder of the highest ranking, particularly noted for his outstanding sportsmanship. His brother Lar Foley was a team colleague, both in hurling and football, through most of his campaigns in the 1950s and 60s and who was also an All Ireland medal winner for Gaelic Football in 1958 and 1963.
Towards the end of his playing career, Foley became interested in politics and was elected to Dáil Éireann as a Fianna Fáil Teachta Dála (TD) for the Dublin County constituency at the 1965 general election. He held his seat until he resigned on 4 November 1970 in protest against the Northern Ireland policy of the Taoiseach, Jack Lynch. Foley's constituency colleague, Kevin Boland, also resigned his seat on the same day. He unsuccessfully contest the 1973 general election in the Dublin County North constituency as anAontacht Éireann candidate.
Des Foley died in Dublin in 1995.