John Declan Mulligan (born 4 April 1938 in Fethard, County Tipperary) is an Irish rock musician, singer and songwriter, best known as a guitarist of American rock band The Beau Brummels. In 1964, he met Ron Elliott, Sal Valentino, and John Petersen during an informal rehearsal at the Irish Cultural Center in San Francisco. After joining the Beau Brummels, who shortly thereafter also added Ron Meagher, Mulligan recorded perhaps his most memorable contribution with the band, the harmonica opening of the hit single "Laugh, Laugh," which reached the top 20 of the U.S. Billboard Hot 100 in February 1965.