Gardiner studied Stanislavski and impulse work with Zygmunt Molik of the Grotowski Theatre Lab at QUT in the late 70`s.​ Iain attended the East 15 school in London, where he trained in Alexander Technique and Voice. Iain worked with Charles Marowitz, Canadian Mime Company, and Ken Campbell, appearing in his 22 hr sci-fi epic, The Warp, at Edinburgh and the ICA London. Iain returned to Australia in 1981.

An early highlight was 'doubling' Judy Davis in Heatwave.​ Iain learnt film technique in ABC dramas, appearing with veterans such as Ed Deveraux & Henri Szeps. Iain was a series regular in Patrol Boat, guested in A Country Practice, Bellamy, Rafferty's Rules, E Street etc., and forged a career in various feature and short films. Iain also worked in experimental & mainstream theater, film and music video production, Iain was a member of the Macau Collective which independently wrote and produced the 1990 feature film, Resistance.