W.J. Brennan-Whitmore was a Wexford journalist and British Army veteran who joined Sinn Fein in 1910. Because of his military knowledge he was appointed to the Volunteers general staff in the lead-up to the Easter Rising. He commanded a position in North Earl Street during the Rising, and was interned with 1,800 other Irish rebels in Frongoch. He later worked for Michael Collins during the War of Independence and supported the Treaty. He retired from the Irish Army in 1926. He was an active member of Clann na Poblachta. He died in 1977 at the age of 91.