Orland Russell Sweeney was born to Robert and Elizabeth Sweeney on March 27, 1884, in Martins Ferry, Ohio. He received his B.S. (1909) in chemical engineering and his M.S. (1910) from The Ohio State University. He received his Ph.D. (1916) from the University of Pennsylvania. He was Instructor of chemistry at The Ohio State University (1910-1911) and at the University of Pennsylvania (1911-1916). After receiving his doctoral degree, Sweeney joined the staff at North Dakota Agricultural College (North Dakota State University) as Associate Professor (1916-1917) of industrial chemistry.

During World War I, Sweeney entered the Trench Warfare Service of the U.S. Army Ordnance Department as Captain. He was promoted to Major, and when the Chemical Warfare Service was organized he was sent to the Edgewood Arsenal in Maryland to develop and operate some of the larger chemical plants. He developed a method for the manufacture of chloropicrin gas which he patented in the name of the United States government.

After the war, Sweeney became Head (1919-1920) of the Chemical Engineering Department at the University of Cincinnati. He joined the staff at Iowa State College (University) as Professor (1920-1952) and Head (1920-1948) of the Department of Chemical Engineering and remained there until his retirement.

Sweeney was a pioneer in the commercial utilization of agricultural waste products. He developed methods for manufacturing paper and wallboards out of cornstalks and corncobs, researched the production of the industrial chemical furfural from oat hulls, and developed processing methods for soybeans. Sweeney's research in synthetic lumber from cornstalks directly resulted in the development of the Maizewood Products Corporation manufacturing plant at Dubuque, Iowa. Sweeney also researched the zeolite process for softening water, the production of Dakin's solution (a medical antiseptic), the manufacture of chemical poison gases, and numerous other topics of interest. His research and inventions resulted in over 300 patents which he held or co-held.

Sweeney served on several professional organizations and governmental boards. He was Chairman of the Greater Iowa Commission and during World War II he served as consultant to the chemical branch of the War Production Board in Washington, D.C. He was a member of the American Chemical Society, Iowa Engineering Society, and the American Institute of Chemical Engineers.

Sweeney married Louella Dubois Smith on October 25, 1919. Together they had two children, Elizabeth and Jacqueline. Sweeney died on April 21, 1958, and is buried at Martin's Ferry, Ohio.