Con Scanlon was born at Moyvane, near Listowel, Co Kerry, in 1954. He joined the Department of Posts and Telegraphs in 1970 and studied at Waterford Regional College and the Limerick School of Electrical Engineering.

A lifelong union activist, he was elected to the executive of the Irish Post Office Engineering Union in the early 1980s and served as president of the Communications Union of Ireland from 1985 to 1990. He was involved in merger talks with the Postal and Telecommunications Workers' Union to form the Communications Workers' Union in 1990.

He became assistant general secretary of the CWU and succeeded David Begg as general secretary in 1997. He is a member of the Irish Congress of Trade Unions' executive and is chairman of the Eircom group of unions and of the ESOT.