Daniel Sullivan, born in 1840 in Millstreet, County Cork, was a multi-instrumentalist best known for his fiddle playing. Part of an early wave of Irish musicians who carried their tradition to the United States in the nineteenth century, he likely arrived in the US in 1874, first settled in South Boston, later Roxbury, and finally Dorchester. From the 1880s onward, census records variously identify him as both a “musician” and a “music teacher,” indicating a dual role as practitioner and pedagogue. Sullivan performed with uilleann pipers including Michael Hobbs and John Harney, but also mentored many noted younger musicians, including the brothers William and Michael Hanafin and Shaun O’Nolan. He also contributed to the circulation of repertoire, and was a source for the piper Patsy Touhey. Sullivan’s stature is clearly reflected in the account of Francis O’Neill, who devoted a chapter to him in Irish Minstrels and Musicians in which he was described as “the most famous professional fiddler in the eastern states.” This regard was echoed in his 1912 obituary, in which he was called “the foremost exponent of Irish music in America.” His son Dan J. Sullivan went on to found the Dan Sullivan’s Shamrock Band in the 1920s.