[citation needed] As a member of Na Fianna Eireann he and companion "Barney" Dalton were arrested for activating an improvised explosive device (I.E.D) along the Dungarvan quay.

circle of twenty, organised by O'Mahony, included Lennon, Pax Whelan and Dan Fraher, all later prominent during the ensuing War of Independence.

After the Easter Rising (in which he and Pax Whelan stopped a train in a futile search for arms), Lennon left Abbeyside School just prior to his sixteenth birthday to devote himself full time to the Irish Republican cause.

Incarcerated with Charlie Daly of Kerry and Sean Moylan he was released prematurely, due to ill health at the time of the third outbreak of Spanish Influenza, in May 1919.

With Liam Lynch on 7 September 1919, Lennon took part in the first attack, since Easter Week 1916, on British military forces at Fermoy's Wesleyan Church.

Circa September/October 1920 he took command of the West Waterford Flying Column as the youngest leader, with Belfast's Roger McCorley, of an active service unit.

Operating from the Comeragh Mountains and the Drum Hills, Lennon, with Great War veteran John Riordan, planned and led the Piltown Cross ambush on 1 November 1920 (the date of the execution, in Dublin, of Kevin Barry) in which a British Army unit was overwhelmed and armaments seized.

[5] In January 1922, staying at Vaughan's Hotel with I.R.A Chief of Staff Liam Lynch (killed by Free State Forces,10 April 1923) of Cork and Charlie Daly of Kerry ("Drumboe Martyr "executed 14 March 1923) he was present at the Mansion House when the Dáil voted to accept the Anglo-Irish Treaty.

[6] Lennon was also the business manager and contributor (aka "George Crolly") to the short-lived art/literary magazine The Irish Review edited by Ulster poet Joseph Campbell.

[7] His return to Ireland was detailed in the novel "Dead Star's Light" (1938) written by Una Troy Walsh under the nom de plume of Elizabeth Connor.

[9] During the "Emergency" World War II period he made contact with English Poet Laureate to be John Betjeman who, as a British Embassy "press attache", had earlier been marked for assassination as a spy by the I.R.A.

Betjeman had written a number of poems based on his experiences in West Waterford including The Irish Unionist's Farewell to Greta Hellstrom, which ended each stanza with the refrain "... Dungarvan in the rain".

According to Professor Diarmaid Ferriter: "An updated medical report in 1944 suggested he was suffering from ‘reactive depression (psychasthenia) and pulmonary disease attributable to military service in IRA,’ and he was estimated to have an 80 per cent disability.

He had ‘recurrent depression, occasional bouts of insomnia and feeling of constriction and nervousness in upper abdomen.’ He could only do work of ‘limited responsibility’ such as cashier jobs.

[12] Unemployed, from the summer of 1944, he re-emigrated, for the second and final time in early 1946, on one of the first post war flights out of the newly opened Shannon Aeroport; ultimately moving to Rochester, New York where he secured an entry level position with the Eastman Kodak Company.

In his later years, Lennon became attracted to the religious tenets of the Unitarians, Quakers and, through a small study group, Zen Buddhism, whose precepts he generally adhered to.

"[citation needed] In 2009 it emerged that a Republican Sinn Féin Cumann had named the Waterford branch of its organization after George Lennon without the permission of his family.

Rebel to Zen Pacifist") and his oil portrait by Ruth Carver was included in an exhibit of Irish art at Rochester's St. John Fisher University entitled "Forgotten Ireland".

In conjunction with the play, the Waterford County Museum presented a series of lectures featuring Dr. Pat McCarthy of the Military History Society of Ireland and Lennon's son, Ivan, who detailed his post 1987 investigation into his father's role in the development of the Irish Free State.

[citation needed] Simon Maguire of Newstalk FM conducted a 2021 interview with Ivan entitled "From Rebel Leader to Peace Activist: The Making of George Lennon."