Séamus Egan was born in Hatboro, Pennsylvania to Irish immigrants Mike and Ann Egan. At the age of three his parents moved the family back home to County Mayo, Ireland.
When Mick Moloney founded Green Fields of America in 1977, Seamus joined up and took lessons from Mick on the banjo. In 1985 he recorded a solo album Traditional Music Of Ireland.
Egan is also the producer for Solas and has worked as producer for other artists, including American singer-songwriter Antje Duvekot, fiddler Liz Carroll, and singer Karan Casey.