Seán McCool (Irish: Seán MacCumhaill) (died 1 May 1949) was a prominent Irish Republican and a former chief of staff of the Irish Republican Army. Imprisoned on numerous occasions, both North and South of the border, he embarked on a number of hunger strikes. He stood as a candidate for Clann na Poblachta before leaving the party as a result of their decision to go into government with Fine Gael.McCool was described by Peadar O’Donnell as "...deeply read but very much the IRA man".