The son of Polish parents who had emigrated to London in 1946, Starzewski's mother and grandmother both worked in fashion. He attended Emanuel School and St Martins College and had an ambition to be a designer from an early age. He has said "I'm third generation".
He first hit the headlines when Victoria Lockwood wore a Starzewski dress for her marriage to Charles, Viscount Althorp, brother of Diana, Princess of Wales, in September 1989. He was also a designer for the Princess of Wales herself.
Starzewski is the principal of the Tomasz Starzewski.
Starzewski has stated his philosophy as "Glamour, elegance, good design, luxury and friendly service".
Tomasz Starzewski fashion shop is located at Pimlico Road. The store has a selection of ready to wear and couture clothes. All the clothes are made on the premises and a discrete service is offered.
In January 2011 Starzewski opened his first retail shop for Interior designers, the store houses a selection of fabrics with different embroidery designs which are customised for clients needs. A design service is provided. Many accessories for home are available and in addition artists such as Emma Sergeant and Fergus Greer are showcased.