Stewart is a highly visual director and writer working in cinema documentaries, commercials, and feature films.

His feature films include writing and directing the Sky Pictures movie Kiss Kiss (Bang Bang), starring Stellan Skarsgard, Chris Penn and Paul Bettany, and Fast Food starring Gerard Butler and Douglas Henshall. He directed the short thriller Slaughterbots which went viral, gaining over 200 million online views and worldwide press. He also wrote and directed the Sky Arts film 'The Cruise' starring Jane Horrocks and Jason Watkins.

In documentary he often specializes in sport, working with stars including Roger Federer, Tiger Woods, and Virender Sehwag. Stewart's productions have won multiple international awards, including a BAFTA in the UK and the Grand Prix in Cannes.

The feature documentaries Stewart has directed include the cinema documentary Kenny, the moving tale of Liverpool FC legend Kenny Dalglish, which won three international best film awards and was released theatrically before showing on BBC1. Stewart also directed feature documentaries A Man Can Dream for Sky Documentaries and Blue Moon Rising, an epic story about Manchester City, released in cinemas to critical acclaim and broadcast on ITV. He has worked both as a director and executive producer on several documentaries for the BBC, including a dramatic behind-the-scenes look at cyclist Geraint Thomas as he battles to win the Tour de France.

Commercials are also part of Stewart's portfolio. He has acted as a creative director for Rolex, and also directed Rolex commercials featuring Roger Federer and Tiger Woods. Stewart directed Channel 4 promos, idents and commercials for the London, Sochi 2014 and Rio 2016, and Japan 2020 Olympics/Paralympics. Other commercial clients include Nike, Adidas, Vodafone, BT, Allianz, BP, Samsung British Airways, General Motors, Renault, Microsoft, Sky, and ITV Channel 4.