Following his retirement from cricket, Gilligan began to work in journalism. He wrote several cricket books, including a history of Sussex cricket in 1932. He became one of the first radio cricket commentators, broadcasting in Australia on the 1932–33 Ashes series and covering subsequent visits of MCC teams to Australia for the Australian Broadcasting Commission. A popular and respected commentator, he established an on-air partnership with former Australian batman Vic Richardson. In Gilligan's obituary, "Wisden" observed "Gilligan was, as may be imagined, a master of the diplomatic comment if any tiresome incident occurred". He was also a member of the BBC radio commentary team for Tests between 1947 and 1954. In 1955, he wrote a book, "The Urn Returns", about the 1954–55 Ashes series, won by England. In England, he wrote about cricket for the "News Chronicle". During the Second World War, Gilligan served in the Royal Air Force as a welfare officer; he was commissioned a pilot officer and rose to the rank of squadron leader.