After the Civil War ended he was appointed Commissioner of the Garda Síochána and by all accounts did an excellent job of turning out a first rate force on a shoestring budget. However when De Valera came to power he lost favour, partially over his record in the Civil War and partly due to his obstreperous nature – especially when dealing with politicians!
He was sacked and became embroiled in party politics as a Leader the ‘Army Comrades Association’ aka ‘the Blueshirts’ and then merged with Fine Gael. His antics as a political leader lowered his esteem in the eyes of many and eventually his Blueshirt movement fizzled out and he parted company with F.G. He led a small expeditionary force to Spain to fight alongside the Fascists there but after a few minor skirmishes the group returned home and disbanded. O’Duffy died in 1944, a broken man living in lonely isolation, though for his past services De Valera granted him a State Funeral.