[1] He was educated at St Mary's grammar school on Barrack Street in Belfast, where he developed an interest in the Irish language.

[1][3] In 1964 he was involved in a riot on Divis Street in Belfast in opposition to the threat from loyalist leader Ian Paisley to march on the area and remove an Irish tricolour flying over the election office of Billy McMillen.

[citation needed] McCann married Anne McKnight who hailed from a strong republican family in the Markets area in Belfast.

[11] Anne's brother Seán sided with the Provisionals after the 1969 split, and was a Sinn Féin councillor on Belfast City Council from 1985 to 1993, and once more from 1997 to 2001.

[20] On 9 August 1971, his unit took over the Inglis bakery in the Markets area, following the introduction of internment without trial by the Northern Ireland authorities.

[15][21] In early February 1972, he was reported to be involved in the attempted assassination of Ulster Unionist politician and Northern Ireland Minister for Home Affairs John Taylor in Armagh City, outside the then Hibernian Bank on Russell Street.

McCann and another gunman fired on Taylor's car with Thompson submachine guns, hitting him five times in the neck and head; he survived, though he was badly injured.

[22] McCann was killed on 15 April 1972 in Joy Street in The Markets by soldiers from the 1st Battalion, Parachute Regiment.

On the morning of his death, he was spotted by an RUC officer who reported his whereabouts to the Parachute Regiment, who were carrying out a road block at the junction of May and Joy Streets in the Markets area at the time.

It was rumoured that McCann was unarmed when he was killed because the Official IRA leadership had confiscated his personal weapon, a .38 pistol.

alleged that McCann's killing was set up by their Dublin leadership who were unhappy with his militancy and favoured a ceasefire.

[1][34][35] Cathal Goulding the Official IRA Chief of Staff, provided the graveside oration in Milltown Cemetery.

Goulding said:[36]By shooting Joe McCann [the British government's] Whitelaws and their Heaths and their Tuzos have shown the colour of their so called peace initiatives.

They have re-declared war on the people...We have given notice, by action that no words can now efface, that those who are responsible for the terrorism that is Britain's age old reaction to Irish demands will be the victim of that terrorism, paying richly in their own red blood for their crimes and the crimes of their imperial masters.Despite this hardline rhetoric, however, Goulding called a ceasefire just six weeks later, on 29 May 1972.

One of the more surprising tributes to McCann came from Gusty Spence, leader of the Ulster Volunteer Force loyalist group.

"He was a soldier of the Republic and I a Volunteer of Ulster and we made no apology for being what we were or are...Joe once did me a good turn indirectly and I never forgot him for his humanity".