His detractors accuse him of being a propagandist and a practitioner of dog-whistle politics. Newspaper headlines talk about him being a "master of dark arts" and an "evil genius."
Lynton Crosby, the Australian political strategist retained by Stephen Harper's Conservatives, says the most important part of campaigning is finding key voters and finding a relevant message that connects with them.
"At its absolute simplest, a campaign is simply finding out who will decide the outcome … where are they, what matters to them, and how do you reach them?" Mr. Crosby said in 2013 during a masterclass to minority youth leaders in Britain.
Mr. Crosby is alleged to have made a similar point in a coarser fashion when he ran Boris Johnson's 2008 London mayoral campaign.
The Daily Mail reported that Mr. Crosby told Mr. Johnson to concentrate on traditional Tory voters instead of chasing "fucking Muslims."
A spokesman for Mr. Crosby told the Mail that he had "absolutely no recollection" of using the term.
Mr. Crosby has also been dogged with accusations that he exploited fears about asylum seekers when he worked for John Howard, Australia's prime minister from 1996 to 2007, who used electoral slogans such as "We decide who comes into this country."
A fifty-something grandfather, Mr. Crosby has lived with wife, Dawn, in Britain for a decade, where he added Mr. Johnson's successful mayoral bid and this spring's re-election of David Cameron's Conservatives to a résumé that already included Mr. Howard's four consecutive victories in Australia.
In an interview this spring with the Telegraph, Mr. Crosby cited familiar tropes as he explained his successes – his belief that the British political elite is out of touch with common folks, that pollsters misread the public mood, that pundits see politics as entertainment and miss the concerns of ordinary voters.
A boring campaign can be a virtue if it means that it focuses on the issues that matter to the electorate, he argued.
"For the voters it's not entertainment, it's a serious issue, it's a serious thing that means a great deal to their lives. It is their future."
His detractors accuse him of dog-whistle politics, where the political message comes with a coded appeal tailored for a specific segment of the electorate.
But it is also about something called the dead cat strategy.
Mr. Johnson mentioned that approach in a comment piece he penned in the Telegraph in 2013.
If you're losing an argument, if you're in a weak position, throw a dead cat on the table, the London mayor wrote.
"Everyone will shout 'Jeez, mate, there's a dead cat on the table!'; in other words they will be talking about the dead cat, the thing you want them to talk about, and they will not be talking about the issue that has been causing you so much grief."
Mr. Johnson attributed the idea to an unnamed person he praised as an "Australian friend" and "great campaigner" with "the rich and fruity vocabulary of Australian political analysis."
Mr. Johnson told the newspaper The Australian that Mr. Crosby got him to concentrate less on his pet projects and made him talk about cutting taxes and a "Crime Manifesto" that promised more policing and safer neighbourhoods.
"Being a straight-talking Australian, with no airs and graces, he can cut through the chaff and he makes you focus on the stuff that really matters to people." Mr. Johnson recalled one unsatisfactory campaign appearance, following which he received a text message from Mr. Crosby: "crap speech, mate."
When Mr. Crosby got involved with the British Conservatives 2015 election campaign, he was praised again by his former clients as someone who could bring the objectivity of an outsider, combined with bluntness, discipline and confidence.
He reportedly told the Tories they had to "scrape the barnacles off the ship," in other words, simplify their message to ensure a smoother sailing.
Mr. Crosby grew up in rural South Australia, where his father was a farmer who later opened an arts and crafts shop.
He earned a degree in economics from the University of Adelaide and, like the rest of his family, supported the Liberals, Australia's right-leaning party.
In his master class at the Patchwork Foundation, he said he got interested in politics when he was 16.
"Not enough people get involved in politics … many people are disillusioned by the political process but it's an important part in society's advancement," he said.
As a Liberal, he ran in 1982 for a seat in the South Australia assembly but lost in the Adelaide district of Norwood. "I turned a marginal Labour seat into a safe Labour seat after campaigning there."
He had caught the political bug, though he realized he was better suited for backroom work.
"In a campaign, what you try to do is either change or reinforce some perceptions that people have in order to influence their behaviour," he said in the master class.
Mr. Crosby has not always been successful.
In 2005, he signed up as campaign manager for Britain's struggling Conservative Party but was unable to help Michael Howard defeat Tony Blair's Labour.
That election also featured its share of controversial slogans from the Conservatives, such as "It's Not Racist to Impose Limits on Immigration" and "How Would You Feel if a Bloke on Early Release Attacked Your Daughter?"
According to the BBC, Mr. Crosby felt he had gotten involved too late in that campaign. "You can't fatten a pig on market day," he said.