He was known as a fine nurturer and scout of young talent, bringing along Peter Shilton, Frank McLintock, Graham Cross and David Nish from the club's reserves.
Gillies took over the Foxes on 8 November 1958 as they sat bottom of the First Division and amidst fan unrest after his predecessor Dave Halliday had recently sold star striker Arthur Rowley to Shrewsbury Town.
[2] Gillies managed to keep Leicester up in his first season, but could only manage the signings of Albert Cheesebrough and Gordon Banks (originally signed as back-up) in the summer of 1959, as the majority of his transfer bids were rebuffed, while scouting missions to watch the young Huddersfield Town striker Denis Law saw him give an unimpressive performance on two separate occasions and Leicester again struggled at the beginning of the season.
Gillies also promoted a young Frank McLintock from the reserves around the same time and although both players made an instant impact and were being touted as stars of the future, it took until December until Leicester's season picked up, eventually finishing in a very respectable 12th position.
Gillies made the sensational decision to drop striker Ken Leek, who had scored in every round of Leicester's cup run, due to his drinking problems.
Two seasons later, in 1962–63, in what is considered Gillies' and often the club's peak,[9] Leicester remarkably chased the double themselves, not only did they reach the FA Cup final but they also sat top of the First Division with just five games to go.
Though most of the disputes were resolved, the loss of hugely influential Frank McLintock to Arsenal for a then club record incoming fee of £80,000 and the unrest over pay saw Leicester slump to 18th in the league.
[2] The sales of Banks and Dougan saw the club decline and although the signings of Lenny Glover and Allan Clarke (the latter for a British transfer record of £110,000) showed promise, a bout of tuberculosis and ill health saw Gillies forced to spend time away from the game and his assistant Bert Johnson took over team affairs between January and March 1968.
[2][11] The illness took its toll on Gillies though and saw his managerial abilities wain and on 28 November 1968, with the club sitting 17th in the league the board sacked his assistant Bert Johnson and first team coach George Dewis.
Gillies and Johnson were one of the first managerial teams in England to experiment with practicing set pieces in training and his switching of Frank McLintock at right-half and Graham Cross at inside-right mid-game, proved revolutionary.