Born in Dexter, Michigan to parents Roscoe P. Copeland and Frances J. (Holmes) Copeland, Royal Copeland graduated from the Michigan State Normal College with a bachelors. In 1888, he taught school in Sylvan Township, Michigan. He graduated from the University of Michigan- Ann Arbor with a degree in medicine in 1889. After graduate studies in Europe, Dr. Copeland practiced medicine in Bay City, Michigan, from 1890-1895. Copeland was admitted to the Homeopathy Society of Michigan, May 21, 1890, and made secretary of the society in October of 1893. He was a professor of Ophthalmology and Otology at University of Michigan Medical School (Homeopathic Department) from 1895 until 1908. During that time period, he also served as Republican Mayor of Ann Arbor, Michigan from 1901-1903, President of the Ann Arbor Board of Education from 1907-1908, and President of the Ann Arbor Board of Park Commissioners.

On July 15, 1908, Copeland married Frances Spalding.

In 1908, Dr. Copeland moved to New York City to take a position as Dean the New York Flower Hospital and Medical College, leaving in 1918 to serve as President of the New York Board of Health. He gained great notoriety in keeping New Yorkers calm during the influenza outbreak of 1918.

In 1922, Copeland ran as a Democrat against first-term Republican Senator William M. Calder. Copeland was re-elected in 1928 over Republican Alanson B. Houghton, the U.S. Ambassador to Britain and a former U.S. Congressman. Copeland was again re-elected in 1934, this time defeating future U.S. Congressman E. Harold Cluett.

During his three terms in the U.S. Senate, Copeland served as Chairman of the U.S. Senate Committee on Rules and Administration from 1933 to 1936 and Chairman of the Committee on Commerce from 1935 to 1938.

In 1937 he was the Democratic nominee for Mayor of New York City, losing to Republican incumbent Fiorello H. LaGuardia. Senator Copeland died in office on June 17, 1938 and was buried at Mahwah Cemetery in Mahwah, New Jersey. He was a member of several honor societies and fraternal organizations, including Delta Kappa Epsilon, The New York Athletic Club, the National Democratic Club, the Elks, the Freemasons, the Knights Templar, the Shriners, the Friendly Sons of St. Patrick, and the Sons of the American Revolution.

At various times Copeland served as President, Vice President, and Secretary of the Michigan Homeopathic Society; President of the American Ophthalmological, Otological, and Laryngological Society; President American Institute of Homeopathy; Vice President of the American Public Health Association; Member of the National Board of Control of Epworth League; Elected three times to the General Conference of the Methodist Episcopal Church; President of the Michigan Epworth League; Member of the Tuberculosis Commission of Michigan; Trustee of Michigan State Tuberculosis Sanitarium;