 Brown promptly took him from East to South Yorkshire on 20 January 1923 for £1,250, converting him into a full-back.Making his debut in a 4–0 defeat to Bury on 27 January 1923, Blenkinsop became a major force behind the rise of the Hillsborough club from struggling at the foot of the Second Division to being promoted as champions at the end of the 1925–26 season, being ever present in his first full season and missing only one match in their promotion winning season.They followed this up by becoming back-to-back champions of the First Division in 1928–29 and 1929–30, Blenkinsop making 41 and 45 appearances respectively.