On migration - consistently one of the most important issues for Reform voters - the Green Party leader could not be further away from Nigel Farage.
Where the Reform leader believes migration has damaged Britain and advocates for "mass deportations", Mr Polanski views it as a positive thing that has benefitted the country.
But in spite of that, Mr Polanski thinks he can win over Reform supporters.
It seems a tall order, given the country's hardening attitude towards migration and the bursts of public anger that has been seen over the use of asylum hotels - most notably in Epping.
But the Green Party leader believes that what is really angering people - the cost of living crisis, wage stagnation, a lack of affordable housing - is not the fault of migration.
He is convinced he can flip the script by highlighting the plight of migrants and by directing the public's anger elsewhere - at billionaires, large corporations and the establishment.
That is what his trip to Calais was all about.
Last week, Sky News joined Mr Polanski in the French town, once home to the "Jungle" refugee camp before it was demolished in 2016, to tackle the "misinformation" he believes surrounds the small boats crisis.
"I think when people have a reality of it, I think the majority of people are actually compassionate," he tells me. "They just want to make sure that our system is fair and it's transparent."
Mr Polanski has now surpassed 100 days as Green Party leader - the point at which the party's fortunes began to change.
Since his election in September, Mr Polanski, a former member of the Liberal Democrats, has taken the Greens in a different direction.
Once known as the party of the environment, the Greens now talk heavily about social and cultural issues that can be divisive - whether that be migration, transgender rights or even the "eco-populism" that some in his own party fear may alienate voters in rural seats.
His stance on these issues has long been attributed to a strategy of courting disaffected Labour voters. In the polls, the Greens are nearly neck and neck with Labour - at 16% and 18% respectively - while there have been multiple councillor defections in recent months.
But when it comes to Reform voters, Mr Polanski believes he can appeal to them by speaking about the other issues that make them angry.
"A Reform voter is very different to a Reform MP, and I have a lot more time for them if they're thinking about voting Reform, because these are the exact people I want to reach out to - to say that your problems are not caused by migration.
"And so what I want to say to those Reform voters is I get your anger, and in many ways your right to be angry. But let's not fuel that anger. Let's make sure that we're challenging power and wealth. And I'm actually your ally in that."
Battle for British sense of fairness
At the heart of the battle over migration is the British sense of fairness.
The Reform leader believes it is unfair that British taxpayer money is being used to fund accommodation for asylum seekers.
To him, it's the British people who are the real victims - not migrants.
For Mr Polanski, what is unfair is that British taxpayer money is indeed being used - but on futile efforts to stop desperate and vulnerable people who should be given a safe haven in Britain to live and work.
He says the government has given the French authorities £476m "on the militarisation of Calais" to deter migrants from boarding a small boat, and this is what people should be angry about.
"That money should be spent on building homes. Yes, for British people and council homes. But also we don't need to pit our housing crisis in the UK against a crisis of a relatively small amount of people who are desperately in need."
The most stark sign of the gap between Mr Polanski and the public came when I asked him what he would say to people in Britain who might not feel sympathy for those seeking to come to the UK in a small boat.
He replied: "I think we need to make racism unacceptable again."
I press him on whether he means that people who do not share his sympathy are racist.
"Well, I think it depends on the context, but we know lots of people have open arms and homes to Ukrainian refugees, as they absolutely should. They're also fleeing a humanitarian war zone. But you can't help but notice that Ukrainian refugees have been accepted. But where is that same kindness and compassion to human beings from Syria, Yemen, Sudan, Eritrea?"
For his critics, this is likely to be seen as a moment where the mask slipped.
Read more:The 'eco-populist' who wants to be the Farage of the LeftWill Farage racism allegations deter voters?
'They're dissatisfied, distrusting, and disapproving'
How can Mr Polanski win over Reform voters when countless polls - and of course Brexit - show that the public want less immigration?
Joe Twyman, co founder and director at Deltapoll, casts doubt on whether Mr Polanski can change the minds of Reform voters who feel passionately about immigration.
But he says, while there is a cohort of Reform voters that Mr Polanski is never going to win over, the dissolution of traditional left and right means there is some crossover between the Greens and Reform.
"There are Reform voters who are going with Reform, if you like, as a default, because they're dissatisfied, distrusting, and disapproving of other political parties - particularly the larger parties of the government.
"And so those people could be wooed to the Greens if they think that Zack Polanski is a more palatable for them as leader, and the policies are more acceptable to them."
Against the backdrop of a cost of living crisis, and after decades of public attitudes hardening towards migration, Mr Polanski has set himself a hard task to change people's minds.
Mr Polanski's critics will no doubt accuse him of wishful thinking - but in the age of personality politics and social media, perhaps it's not the story that counts but the way it is told.
