He was born in Rochester, New York, to George Elbert Barker and Harriet Whitbeck Barker. Presbyterians, they became interested in New Thought upon attending lectures related to this spiritual philosophy and movement. In 1916 both parents became very actively involved with the Unity Center formed in Rochester that year, with Raymond attending the Sunday school. The minister, Cora French Williams, exerted a great influence on the young Raymond, who soon became her "crown prince." Very early he participated in Center activities, and in his teen years he was already assuming responsibilities at the Center afternoons after school. This was the beginning of his functioning at a young age in quasi-ministerial capacities. He quickly accepted a call to the Assistant Ministry of the Church of Universal Truth in Toledo, Ohio, followed by a return to the Rochester Unity center, where he spoke Sundays and Wednesdays. In 1935 he began his formal studies one month each summer, 1935-1938, at Unity headquarters, Lee's Summit, Missouri. While still formally a student, he organized a Unity Center in Syracuse, New York.
In June 1940 he was ordained at Unity School by Unity co-founder Charles Fillmore. However, later that year his visit to Los Angeles and his meeting with Religious Science founder Ernest Holmes exerted the next big influence on his life, one that attracted him to Religious Science and, in 1944, acceptance of a co-ministry with Elizabeth Carrick-Cook at the San Francisco Institute of Religious Science. He had first met Carrick-Cook (as she became known) at the 1940 International New Thought Alliance Congress that she and her Absolute Science Center hosted. This marked the beginning of a close friendship that introduced Dr. Barker to the teachings of the English metaphysician Frederick Lawrence Rawson, whose work in America had been continued by Mrs Cook's late husband, Jay Williams Cook. Mrs Cook merged her activity with Religious Science at the same time that Dr Barker joined Mrs Cook at the newly formed Religious Science Institute in San Francisco. This, however, he resigned in 1945, later that year to begin the formalization, at Dr. Holmes' request, of a Religious Science ministry in New York City.
On February 1 1946, he founded the First Church of Religious Science in Manhattan. By 1949 services were being held at New York's prestigious Town Hall. Three years later the new church acquired the building at 122 W. 55th St. and in 1966 moved from there to ownership of the still more desirable 14 East 48th St, around the corner from 5th Avenue. Even these generous accommodations were not sufficient for the hundreds attending Dr. Barker's meetings and classes, so arrangements were made in 1969 for the Church to hold its Sunday meetings at Alice Tully Hall in the city's famous Lincoln Center. Dr Barker also had a weekly program on New York City's metropolitan-area radio station WOR. Some of his students included future Religious Science leaders Stuart Grayson and Louise Hay. He was a president of the International New Thought Alliance (1943-46) and of Religious Science International (1954-57).
Upon Dr. Barker's retirement from the ministry in 1979, he was succeeded by Dr. Stuart Grayson. Dr. Barker took up residence at Rancho Mirage, Calif., where he continued actively as a writer and guest speaker until his decease on January 26, 1988. Memorial services were held for him at the New York and Palm Desert (Calif.) churches of Religious Science. At the latter church, Dr. Robert Bitzer, founder of the Hollywood Church of Religious Science and one of the Religious Science movement's earliest workers and organizers, eulogized Dr. Barker as having done more for Religious Science than anyone since founder Ernest Holmes.