Geoff has been married to Pauline since 1961 and has five children.
After attending St Virgil's College, Hobart, Hook started as a cadet press artist on the Hobart Mercury and completed a course in Graphic arts at the Hobart Technical College (now Tasmanian School of Art, a faculty of the University of Tasmania) which included tuition in Fine Arts under Jack Carington Smith, Margaret Chandler, Harry Buckey and Edith Holmes.
He started his career as a press artist and part-time cartoonist on the Hobart Mercury drawing under the name "Jeff". He moved to Melbourne and started at The Sun News-Pictorial in 1964. Geoff became the full-time cartoonist for The Sun News-Pictorial (later to be merged with the afternoon newspaper The Herald to become the Herald Sun) soon after. It was shortly after that Geoff started hiding in his cartoons what became his "trademark", a fish hook, and looking for the hidden fish hook became a widespread morning pastime amongst readers of The Sun News-Pictorial.
Geoff first gained international recognition in 1967 for his cartoon about the end of the Six-Day War, "The three wiser men", which was republished widely outside of Australia, including in The Times.
In 1987, Geoff won the award for Humorous Illustration in the Australian Black and White Artists Club's Bulletin Awards. Also in 1987, Geoff won the award for the Best Political Cartoon at The International Cartoon Festival at Knokke-Heist, Belgium, and in 1991 he won the award for Best Press Cartoon at the same Festival.
Geoff retired from the daily Herald Sun in early 1993, but continued to freelance doing a regular editorial cartoon for the Sunday Herald Sun while devoting his time primarily to painting. This continued until the year 2000, when he largely stopped cartooning after holding his first exhibition at the Australian Guild of Realist Artists (AGRA) gallery and pursued his love of painting full-time. Since then Geoff has widely exhibited at regional art shows and galleries in Australia, and also held a second exhibition at the AGRA Gallery in 2005.
Over the course of his career Geoff has also done numerous cartoons and illustrations for papers, magazines and 46 books, including two children's books Harry the Honkerzoid and Planet of the Honkerzoids written by one of his sons, Brendan, and a children's book of his own, Jamie the Jumbo Jet, which was first published in the mid 1970s, and revised and reprinted in 1998.
Since retiring from full-time cartooning, Geoff was awarded the Australian Black and White Artists Club's Silver Stanley Award for lifetime achievement in 1998, and on 20 March 2009, he was awarded a lifetime achievement award by the Melbourne Press Club. In January 2012, he was awarded an OAM for "service to the print media as a political and social commentator, and as a cartoonist",.
He is a Life Member of the Australian Black and White Artists Club (now Australian Cartoonists' Association), Life Member of The Melbourne Press Club, Life member of The Media, Entertainment and Arts Alliance, Life Governor of the Royal Victorian Institute for the Blind, and a Patron of the Amputees Association of Victoria. He is also a member of the Australian Guild of Realist Artists and the Peninsula Arts Society.
- The British Cartoon Archive, University of Kent. http://www.cartoons.ac.uk/browse/cartoon_item/anytext=geoff%20hook?page=2
- "Previous Stanley Award Winners", Australian Cartoonists Association. http://www.abwac.org.au/?page=211
- de Becker, Paul (1987). CARTOONS 1987 International Cartoon Festival Knokke-Heist. Belgium: Davidsfonds/Leuven. ISBN 90-6152-487-3.
- de Becker, Paul (1991). CARTOONS 1991 International Cartoon Festival Knokke-Heist. Belgium: Davidsfonds/Leuven. ISBN 90-6152-742-2.
- "Reporters Scoop Top Journalism Award", The Age, 21 March 2009. http://www.theage.com.au/national/age-reporters-scoop-top-journalism-award-20090320-94hg.html
- Governor-General of Australia, Australia Day 2012 Honours Lists. http://www.gg.gov.au/res/file/2012/honours/ad2012/Media%20Notes%20OAM%20(F-L)%20(final).pdf
- "Retired cartoonist Geoffrey Hook receives Medal of the Order of Australia", The Herald Sun, 26 January 2012. http://www.heraldsun.com.au/news/more-news/retired-cartoonist-geoffrey-hook-receives-medal-of-the-order-of-australia/story-fn7x8me2-1226253856264