Cornelius G. M. Hartnett (1951 – 17 December 2019) was an Irish Gaelic footballer who played for Cork Championship club Millstreet. He was a member of the Cork senior football team for six seasons, during which time he usually lined out as a left wing-back. Hartnett began his Gaelic football career at club level with Millstreet. He broke onto the club's top adult team as a 17-year-old in 1968 after enjoying a hugely successful career at underage level that saw him secure five successive Duhallow Minor Championship titles. At inter-county level, Hartnett was part of the successful Cork minor team that won back-to-back All-Ireland Championships in 1968 and 1969 before later winning back-to-back All-Ireland Championships with the under-21 team in 1970 and 1971. He joined the Cork senior team during the 1969–70 National League. Hartnett eventually became the first-choice left wing-back and made numerous National League and Championship appearances in a career that ended with his last game in 1975 before effectively being dropped from the team. During that time he was left wing-back on Cork's 1973 All-Ireland Championship-winning team. Hartnett also secured three Munster Championship medals. Playing career Millstreet Hartnett joined the Millstreet club at a young and played in all grades at juvenile and underage levels. He enjoyed a hugely successful underage career, winning five successive Duhallow Minor Championship medals between 1965 and 1969. On 29 November 1968, Hartnett was still just 17-years-old when he lined out at left wing-back for the Millstreet senior team in the Tadhg Crowley Cup final. He ended the game with his first silverware at senior level after a 2–05 to 0–07 defeat of St. Finbarr's. Cork Minor and under-21 Hartnett first played for Cork as a member of the minor team during the 1968 Munster Championship. He made his first appearance for the team on 5 July 1968 when he lined out at left wing-back in a 3–08 to 1–06 defeat of Waterford. On 14 July 1968, Hartnett won a Munster Championship when he again lined out at left wing-back in Cork's 2–13 to 0–02 defeat of Kerry in the final. He won an All-Ireland medal on 22 September 1968 following Cork's 3-05 to 1–10 defeat of Sligo in the All-Ireland final. On 20 July 1969, Hartnett lined out in a second successive Munster final against Kerry. He ended the game with a second winners' medal after the 3–11 to 0–12 victory.