[1] Although Downie was born in the U.S. state of Wisconsin, his father was Scottish[2] and he swam for Great Britain, Scotland, and the Warrender Baths Club in Edinburgh.

[5][6] Downie represented Great Britain at the 1973 World Aquatics Championships in Belgrade, Yugoslavia where he broke the Scottish record for the 200-metre freestyle.

[3] and won a silver medal at the 1975 World Championships in Cali, Colombia as part of the British 4x200-metre freestyle relay with Alan McClatchey, Gary Jameson, and Brian Brinkley.

At the same championships he won a bronze medal as part of the British 4x100-metre medley relay with David Wilkie, James Carter and Brian Brinkley.

[11] In 2004 Downie was a doctor (pulmonologist) at The Brody School of Medicine at East Carolina University[2] and in 2014 he was practicing in Mount Pleasant, Texas at the Titus Regional Medical Center.