Ferriss served as pitching coach for the Red Sox under manager Pinky Higgins from 1955 to 1959 before moving on to Delta State University as head coach in 1960. He held that role until early 1967, when he left Delta State to take the role of assistant athletic director at Mississippi State University. Ferriss returned to Delta State in mid-1968, and he again served as head coach from 1970 until retiring after the 1988 season. His 639–387–8 record as Delta State head coach ranks him among all-time national coaching leaders at the NCAA Division II level. He guided Delta State teams to the NCAA Division II playoffs in eight of his last twelve seasons, including three trips to the NCAA Division II Baseball Championship resulting in finishes of third (1977), second (1978), and third (1982). Gulf South Conference championships came in 1978, 1979, 1985, and 1988, along with a second-place finish in 1981 and third-place in 1982.