During this period he held membership in the Algoma Steelworkers Union and later, several positions and executive offices with the successor union, Local 2251, United Steelworkers of America. In 1947 he became a District Staff Representative of the USWA and in 1967 he was appointed Area Supervisor. Mr. Barker was appointed as a Canadian representative to the International Labour Organization Convention in Geneva, Switzerland.

In 1958 Mr. Barker assumed the leadership in the establishment of the Group Health Centre. He served as Chairman of the Board of Directors for eleven years and then stepped down to serve as a Board member in 1973 until 1981. His service to the Centre was recognized in 1982 when he was awarded the Group Health Centre Award of Appreciation and made a "Board Member Emeritus."

The contributions of Mr. Barker to his community were recognized by the City of Sault Ste. Marie which awarded him its Medal of Merit in 1973 and by Laurentian University which awarded him an Honourary Doctor of Laws Degree in 1979.