McGonigal was born in New South Wales, grew up in Singleton, NSW and attended Newington College (1966-1967). He studied Arts/Law at Sydney University (1968-1975) graduating in Arts in 1971 and Law in 1975.

McGonigal has led Antarctica courses at the University of Sydney with guest lecturers Sir Edmund Hillary, Andrew Denton, Lincoln Hall and Phillip Law and has taken tours of Antarctica for the university.

McGonigal has twice travelled around the world on a motorcycle and, in 1998, was the first person ever to motorcycle on all seven continents.

McGonigal is a diamond-badged sailplane pilot and was part of the team that set the current Australian height record.

McGonigal's photographs have been used by Qantas and the Australian Tourist Commission and have appeared in all major Australian publications and internationally in the Sunday Times, Esquire and the Los Angeles Times.

In 2000, with Dr Lynn Woodworth, McGonigal wrote most of a 608-page book on Antarctica and the Arctic. He was the photographer and wrote sections on geography and history while Woodworth wrote most of the wildlife section. Antarctica - The Complete Story was published the following year in Australia and North America and in the UK and in Germany in 2003. The Japanese language edition was published in 2005. The abridged 224-page “Antarctica - The Blue Continent” was published in 2002 and has been translated into Russian, Dutch, French and Italian. In October 2008 an updated version, "Antarctica - Secrets of the Southern Continent" was simultaneously released in North America and Australia.