Samuel Clarence Cooper started his engineering career in 1924 in Crosbyton, Texas, in 1924 as a bookkeeper, abstractor and rodman. In 1929 he left Crosbyton to join the Texas State Highway Department and County Surveyor in Sweetwater, Texas. After one year of service, Cooper joined the Municipal Engineering Company of Dallas as a topography recorder. He served this firm and other firms in several counties in Texas until 1933 when he again accepted a position with the Texas State Highway Department and was stationed in Coleman, Texas. He served there as instrument man, office engineer and inspector until 1935 when he was made city and county engineer of Coleman in which capacity he served until 1942.

Following that, Cooper became associated with the firm of Haynes & Strange, Parkhill, Voelcker & Dixon. He served first as a design engineer in Lubbock and later was made chief engineer of the Albuquerque branch office. From 1943 to 1945 Cooper was city engineer of Big Spring, Texas, where he was in charge of design, construction and operation of varied municipal facilities. Cooper was one of three founders of Parkhill, Smith and Cooper and was continuously associated with the firm since its inception in 1945.