Muir is a partner, currently based in Sydney, Australia. He completed his architectural studies in 1994 at Edinburgh University and joined the practice the following year. Early projects include Canary Wharf Underground Station in London and the Clark Center laboratory in California. Muir was project architect on Deutsche Bank Place in Sydney from 2002 to 2004 and later relocated to Abu Dhabi to develop Masdar City - a masterplan for a sustainable city. In recent years Muir has specialised in rail projects.