MacManus was born in
Harlesden, north-west London, which at the time had a large
Irish community. His father,
Seán MacManus, a native of Gubaveeney, near
Blacklion,
County Cavan, had moved to London in the 1960s to find work. There he met and married Helen McGovern, a native of
Glenfarne,
County Leitrim. In 1976, the family returned to Ireland to live in the
working-class Maugheraboy area of
Sligo town so that the boys could be educated in Ireland. He was educated to primary level at
Scoil Ursula Primary School,
Strandhill Road, Sligo and St. John's
Marist Brothers National School, Temple Street, Sligo to secondary level at
Summerhill College and at third level at
Sligo RTC. MacManus played football for local junior teams Collegians and Corinthians, and
Gaelic football for both Saint Mary's GFC of Maugheraboy and Coolera GFC of
Strandhill. His father Seán, who at the time was a leading republican, later became Mayor of Sligo. He was the secretary of the
County Sligo anti H-Block Committee in the 1980s. He was the first
Sinn Féin Mayor in the
Republic of Ireland since the beginning of
The Troubles in 1969. His father was also involved in the negotiations leading to the
Good Friday Agreement. Joe's younger brother,
Chris, was a Sinn Féin Councillor for Sligo Borough Council and Sligo County Council for many years and is an
MEP since March 2020. ==Paramilitary activity==