Betty is began playing the piano at age 5. The upright piano arrived in the MacMaster home in the early thirties, shipped to the tiny village of Judique by train, arriving on the Judique Flyer complete with a cardboard chart showing the black and white keys and the names of the notes.

Although Betty had a couple of years of piano training, all of her Cape Breton piano playing is done by ear. At fourteen years of age, she started playing dances with her brother Buddy and has been accompanying fiddlers for dances and concerts ever since.

Betty has taught at the Ceilidh Trail School of Music in Inverside Cape Breton at fiddle tunes in Port Townsend in Washington, USA and Ceolas in South Uist Scotland. She has been on numerous recordings accompanying and she also joined in on the CD Cape Breton Fiddle and Piano Music as part of the Beaton Family of Mabou a Smithsonian folkways recording. In more recent years, she can often be found accompanying her fiddler husband, Kinnon Beaton.