 At Southend, McMillan was deployed in a more withdrawn midfield role than he had been with Manchester United and Wrexham, and so he scored just five goals in nearly 80 appearances for the Shrimpers.After just over two seasons with Southend, a £2,000 move to Wrexham's local rivals Chester followed, but he was released to sign for Stockport County at the end of the 1969–70 season.At Stockport, McMillan reverted to his old position in the forward line and amassed a total of 29 league goals in 74 appearances before a back injury forced his retirement in 1972.