 Drafted as the 11th pick in the third round (37th overall) of the 1951 NFL Draft, Grandelius played one season (1953) in the NFL for the New York Giants.He rushed 108 times for 278 yards with 1 touchdown and 3 fumbles and also had 15 receptions for 80 yards.Grandelius became an assistant coach at his alma mater in 1954 under newly-promoted head coach Duffy Daugherty and stayed for five seasons, through 1958.