Hallaran, a second row forward, gained 15 Ireland caps between 1921 and 1926. He also played at various times for the Barbarians, Edinburgh Wanderers, Lansdowne, Surrey, Royal Navy and United Services. A capable boxer, Hallaran was officers' heavyweight champion of both the Grand Fleet and Royal Navy.[2]
Hallaran had attained the rank of commander by World War II and was serving on the HMS Springbank in 1941 when he drowned rescuing a stoker who had fallen overboard. After guiding the sailor to safety, Hallaran was taken by a wave and suffered a fractured skull, having been crushed between two vessels. He was posthumously awarded the Albert Medal for gallantry.[3]