[2] He is of Ukrainian descent on his maternal side; his mother was born in the Kharkiv region of Ukraine and arrived in Australia in 1949 with her parents as displaced persons.

He also worked briefly as media adviser to Senator Rod Kemp, before returning to state politics as chief of staff to opposition leader Denis Napthine from 1999 to 2002.

In September 2011, Guy overruled Bass Coast Shire and rezoned a 5.7-hectare farming property at Ventnor, Phillip Island, from farmland into the township making it available for development.

[10] Opposition to the rezoning included American singer Miley Cyrus, who tweeted to her 2.5 million followers that "Phillip Island is such a magical place, it would be a shame to see it change".

[13] The developer behind the rezoning, Ms Carley Nicholls, claims to have received a favourable hearing from Matthew Guy when she briefed him on the scheme at a "kitchen table meeting" in her home months before he controversially approved it.

[14] In defence, Guy stated in court documents that he acted in error in rezoning the land but had relied on the advice of ministerial staff.

"This may be winnable @ law but this is a political fight and it is unwinnable," Guy is quoted as saying in confidential notes made by the Victorian Government Solicitor's Office in July 2013.

[17] In early 2014, Guy overruled his department to block the release of freedom of information documents about the botched rezoning of farmland on Phillip Island.

[18] In March 2014, Mr Brouwer found that Guy was ultimately responsible for the rezoning decision and that he had refused to hand over important documents requested as part of his investigation.

[19] During his tenure as planning minister, Matthew Guy became known for approving a large number of high rise buildings apartment towers in the CBD and Southbank, and for rezoning swaths of land at Fishermans Bend, Footscray and North Melbourne for high-rise development.

This approval drew criticism from the Melbourne Lord Mayor Robert Doyle, who was concerned the building would cast a shadow over the Shrine of Remembrance, and from planning academic Professor Michael Buxton, who referred to Guy as "Mr Skyscraper.

[24] In June 2014, Australia 108 was approved for a second time with a height reduction after Fairfax Media revealed the building violated federal air safety regulations for Essendon Airport.

[25] Opposition planning spokesman Brian Tee said the minister, by approving so many skyscrapers so quickly for Melbourne's CBD, was displaying "a complete disregard for the impact these developments are going to have" over a 15- or 20-year period.

[25] Before the 2010 state election, the then Liberal–National opposition announced plans to restrict wind farm developments across Victoria, within two kilometres of homes and in the vicinity of regional towns.

On 29 August 2011, Minister Guy delivered on this commitment through approval of Amendment VC82 to the Victoria Planning Provisions, prohibiting new wind turbines within two kilometres of homes unless there is written consent from the homeowner.

The new planning laws were criticised by academics on the basis that they would: entrench fossil fuel generation in the state, make it harder for Victoria to move towards renewable energy, put local above global concerns, and treat wind as more dangerous than coal.

[33][34]Pacific Hydro stated that they are not looking at new greenfield developments in Victoria and Windlab Systems stated that the Government's planning laws had "gone too far" and the company was moving all staff to Canberra[34][35] The then Premier Ted Baillieu had opposed wind energy since the early 2000s, raising concerns about the approval of projects at Portland in western Victoria and the Bald Hills proposal in Gippsland.

"[35] In July 2014, Guy announced a small adjustment to the planning laws allowing existing wind farm permits to be amended, which may assist with upgrading turbine technology.

Senior Labor politician Luke Donnellan accused the Liberals in the Victorian parliament of taking "blood money… stained with misery and crime".

[50] In August 2017, media outlets reported that Guy attended a dinner with Tony Madafferi at Lobster Cave restaurant Beaumaris, owner of the La Porchetta pizza chain, who has been accused in court by police of being a high-ranking member of Melbourne's Calabrian Mafia.

As the debate went on, Liberal MLCs Craig Ondarchie and Bernie Finn requested leave for religious reasons due to Good Friday observance, and were each granted a pair.

On 3 April, Guy defended this apparent breach of parliamentary convention, saying the "means were absolutely justified", that he had ordered their return, and was proud that their actions had saved the Country Fire Authority (CFA).

[60][61] In February 2022, Guy, along with Peter Walsh, David Davis, Gary Blackwood and Melina Bath, were fined $100 each for breaching face mask rules, after the Coalition MPs were photographed maskless while attending an event in Parliament House.

[74][75] On 19 November 2022, Guy dumped Renee Heath, the first ranked candidate for the Liberal ticket in the Eastern Victoria Region of the upper house Victorian Legislative Council, from the party after her far-right conservative religious views, including support for Conversion therapy, were bought to light by a newspaper investigation.

[84] As of 2018[update], Guy was a member of the St Kilda Saints, the South Sydney Rabbitohs, Radio 3RRR and the National Trust of Victoria.