Belfast-born, Walter McMillen established a good reputation at right-half  in his native Ulster with the likes of Cliftonville and Distillery. He was brought to England by Arsenal for trials, but it was Manchester United who decided to offer him terms, signing him in July 1933. In three years at Old Trafford he played 27 times and jumped at the chance of first team football when Chesterfield offered £2,000 to United and a rare maximum wage to the player himself. He came to establish himself as a key player here, as the newly-promoted Spireites found their feet in Division Two before the second world war. He was allowed to leave as Norman Bullock rebuilt in 1939: he went to Millwall for £2,000 but the onset of war meant that Chesterfield saw hardly any of the fee, since regulations were passed soon after war broke out that allowed clubs to default on such debt to other teams.

Walter made seven appearances for Ireland: four came during his time at Saltergate, making him the first person to receive a full international "cap" while on the club's books and the club's most-capped player, along with Mark Williams.  He won two amateur caps early in his career, and was selected for the Irish League side during a spell as a wartime `guest' at Linfield and Glentoran.

During his early career, he was a Gibson Cup winner with West End, and a Gold Cup winner with Cliftonville Amateurs.  Quiet and unassuming, Walter was valued as a `club man' as much as a fine, cultured halfback.  He had excellent ball control and was a judicious passer who out-manoeuvred opponents by anticipation and timing.  His scoring record for a halfback was creditable, by the standards of the day. After football he retired to his native Ulster.

For Chesterfield: 85 league appearances, 17 goals.