In 1993 graduated from Heriot Watt University, Edinburgh in Bachelor of Science in Clothing Management. Peter then moved to London to enroll at the prestgious Royal College of Art where he graduated in Master of Arts in Fashion Menswear. Specialising in men’s bespoke tailoring, Peter practiced and perfected his skills in pattern cutting, hand made bespoke tailoring and styling. It was whilst studying at the RCA that Peter became the first British entrant to win the coveted Italian tailoring and design competition, the ‘Ago D’Oro’ (Golden Needle) hosted by Brioni in Italy. 

In 1995, appointed Designer at Kilgour, French & Stanbury one of the the most prestigious tailoring houses on Savile Row where he created Kilgour’s first ever ready-to-wear collection, launched in Autumn 1996. In 1998, was appointed Head of Menswear Design at Dunhill, London, responsible for the Global design of ready-to-wear collections and Japanese licensing collections including tailoring, shirts, casual wear, outer wear, knitwear, golf wear and accessories. The lure of managing the design of all contracted collections including for Ralph Lauren, Turnbull & Asser, Hackett and Huntsman saw Peter accept the position of Design Director at Chester Barrie, Savile Row London before starting his own business.

In 2003, announced the creation of his own Scottish company Peter Johnston Limited, A flagship townhouse was opened in the centre of Edinburgh, establishing his own-label private brand ‘PETER JOHNSTON’ providing a bespoke tailoring service. The townhouse is located in the very prestigious "New Town" district of Edinburgh where private bespoke tailoring clients are wardrobed.