[1] Mortimer is notable as one of the first two Australians (with Tim Macartney-Snape) to successfully climb Mount Everest, on 3 October 1984.
[4] Mortimer was born in 1952 in Sydney, New South Wales and grew up around Gladesville and Bondi Junction.
He then worked as a survival-training instructor and as a Scientific Affairs Adviser for the New Zealand Antarctic Division.
[8] In 1994, Mortimer summited Chongtar in China, which was then the world's highest unclimbed peak.
[9] The crux pitch on the North Face of Everest route pioneered by Mortimer is known as "Greg's Gully".