[6] He fought in the O'Connell Street area during the Battle of Dublin, evading capture during the evacuation of the Hammam Hotel.
[citation needed] In the Leinster Senior Cup final of 1926, he played well, but retired injured, as Bohs beat Shelbourne 2–1.
[9] In 1926, Stynes emigrated to the United States, settling in New York City,[14] where he worked as an accountant with Cartier jewellers.
[22] In 1938, Stynes signed on behalf of the American GAA an Irish-American petition for the release of Frank Ryan, the IRA leader imprisoned by Franco's Nationalists during the Spanish Civil War for fighting in the International Brigades.
[24] He was politically active in Clan na Gael, and after 1948 was leader of the few branches that had remained loyal to the rump of the IRA.
[25] In 1949, Stynes supported a decision, which split the Clan, to use its funds for a monument in Dublin to Seán Russell rather than retaining them for a future IRA campaign.
[30] Joe Stynes's brother Peter played Gaelic football for Dublin in the 1925 and 1926 Leinster championships,[31] and got a 1926 League runners-up medal.
[32] Peter was the father of Jim Stynes, Australian rules footballer,[3] and his brother Brian, who won an All-Ireland with Dublin in 1995.