After studying theatre design at Nottingham Trent University, Glazer started out directing theatre and making film and television trailers, including award-winning work for the BBC. In 1993 he wrote and directed three short films of his own ("Mad", "Pool" and "Commission"), and joined Academy Commercials. He has directed popular campaigns for Guinness (Swimblack and Surfer) and Stella Artois (Devils Island). Since the mid-1990s he has directed a number of music videos, and was named MTV Director of the Year 1997. His work in these areas is often noted for its originality.
In 2001, Glazer directed the "Odyssey" spot for Levi Strauss Jeans.
In 2006, Glazer directed the second Sony BRAVIA TV advertisement, which took 10 days and 250 people to film. It was filmed at an estate in Glasgow, and featured paint exploding all over the tower blocks. Later the same year he was commissioned to make a television advert for the new Motorola Red phone. The advertisement, showing two naked black bodies emerging from a lump of flesh rotating on a potter's wheel, was due to air in September 2006 but was shelved by Motorola. The advertisement was to benefit several charities in Africa.