He was born on February 23, 1880, in Lansing, Michigan, the son of Edward Cornelius Chapin and Ella Rose King. He attended the University of Michigan.

Chapin headed the consortium of businessmen and engineers that founded the Hudson Motor Car Company in 1908. The company was named for Detroit merchant Joseph L. Hudson, who provided the majority of capital for the operation’s start-up.

Chapin married the former Inez Tiedeman in 1914. The couple had six children. One son, Roy D. Chapin Jr., would also pursue a career with Hudson Motor Company and eventually leading American Motors Corporation (AMC).

Chapin was also behind the 1918 formation of the Essex Motors Company, a subsidiary of Hudson. Essex is notable for developing the first affordable mass-produced enclosed automobile in 1922. Because of the success of the inexpensive enclosed Essex Coach line, the American automobile industry shifted away from open touring cars in order to meet consumer demand for all-weather passenger vehicles.

In 1927 he replaced Clifton as the head of the National Automobile Chamber of Commerce.

In 1927, Chapin commissioned noted architect John Russell Pope to design a residence for his family at 447 Lake Shore Road in Grosse Pointe Farms, Michigan. Pope later designed the Jefferson Memorial, National Archives Building and National Gallery of Art in Washington, D.C.. Bryant Fleming landscaped the grounds which included 600-year-old yews imported from England. Mrs. Chapin occupied the residence until her death in 1956 when Henry Ford II and wife Anne purchased the property. Ford owned the estate until 1983 when he demolished the house and divided the land to construct condominiums.

After building Hudson into one of the most profitable independent American automobile manufacturers, Chapin left Hudson for the Hoover administration upon his appointment in 1932.

Chapin returned to Hudson in March 1933. His final three years were spent trying to save the company from the effects of the Great Depression. He died in Detroit, Michigan on February 16, 1936. He was succeeded at Hudson by A.E. Barit. He is buried in Woodlawn Cemetery.

In 1954, Nash Kelvinator acquired Hudson in a friendly merger. The resulting company, American Motors Corporation (AMC), continued operation until Chrysler acquired it in 1987. Chapin’s son, Roy D. Chapin Jr., served as chairman and chief executive officer of AMC and led the automaker to the acquisition of Kaiser Jeep Corporation in 1970. Chapin was inducted into the Automotive Hall of Fame in 1972. His grandson, William R. Chapin, was named president of the Automotive Hall of Fame in 2010.