Ernest Coombs was born in Lewiston, Maine, and pursued a career in children's entertainment after attending North Yarmouth Academy in Yarmouth, Maine. He was assistant puppeteer to Fred Rogers, working with him at WQED in Pittsburgh on Rogers's noontime program, The Children's Corner. Rogers and Coombs became close friends and when Rogers was offered a show in 1963 at the Canadian Broadcasting Corporation, he invited Coombs to join him in Canada to work on an early version of Mister Rogers' Neighborhood, called Misterogers. Rogers moved back to the United States three years later, but Coombs decided to stay in Canada, joining a new TV series called Butternut Square. Butternut Square ran from 1964 to 1967. During the run, Coombs appeared as the character in the Poor Alex Theatre in The Tickle Trunk, starring Mr. Dressup with Casey and Finnegan.