A central defender who joined Tottenham as a first-year scholar in the Spurs Academy in July 2004.  Leigh was previously on the books of Swindon Town and he represented Hampshire at under-15 and under-16 level, captaining the England under-16 side, but he had not made a first team appearance for the Wiltshire club.  He has been capped for his country at under-17 level and went straight into the under-18 side for Spurs.

Mills maintained a steady development through the youth sides and in 2006-07, he broke into the reserves and played regularly, showing good composure and skill in impressing youth coach Clive Allen.

In May 2008, Leigh signed a new professional contract with Spurs.

Went out on loan at the start of the 2008-09 season with Brentford, but this was quickly cancelled and he spent a loan spell at Gillingham, where he impressed from the start of the season, but returned to Tottenham in December.

A month later, the club announced that his registration had been cancelled.

Had been on trial at Aldershot, but was not taken on at the Recreation Ground.