[8] He was one of two players who made his debut for the Saints in a 2–0 victory against Manchester City on 16 August 1980, the other being England international Kevin Keegan,[9] whose arrival at The Dell overshadowed that of McCartney.
[2] McCartney failed to settle back in the First Division and, after a run of 15 consecutive matches, including a 7–1 defeat at Watford in the League Cup,[10] he lost his place at left-back to Nick Holmes.
[11] After a total of 24 appearances, with one goal, McCartney returned to the Third Division with Plymouth Argyle in August 1981,[3][4] for the same fee that Southampton had paid to Carlisle a year earlier.
[8] McCartney made his debut at Home Park on 15 August 1981 in a Football League Group Cup match against AFC Bournemouth which ended goalless.
[3] Described as a "tough-tackling full-back", McCartney made a total of 62 appearances, scoring six goals, for Argyle before returning to Carlisle just before the end of the 1982–83 season[3] in an exchange deal with Gordon Staniforth.
[2] In the summer of 1988,[2] McCartney returned across the border to Scotland joining Gretna of the Northern League Division One,[15] initially as a player-manager, becoming full-time manager the following year.