Misty Thackeray has described Freedom Party leader Geert Wilders, who said Islam was the biggest threat to civilisation, as "great".
He also said it would have better had sacked Ukip Scotland leader Lord Christopher Monckton silently vanished "up the Orinoco."
As revealed by the Sunday Herald, Ukip in Scotland is imploding due to tensions between senior members. Of nine shortlisted candidates for the European election, at least six quit over the alleged tactics used by one candidate, Otto Inglis.
Ukip chief Nigel Farage then sacked Monckton by email. That led to Scottish chair Mike Scott-Hayward and fundraiser Malcolm Macaskill quitting in protest.
Local branch officials also resigned in a show of solidarity with Monckton, who said Ukip north of the Border had been "wiped out".
Thackeray said he had been asked to act as Scottish chairman until the next annual general meeting, but his hardline right-wing views are causing alarm.
The Glasgow-based 52-year-old, described as a security consultant on a business database, praised Wilders on Facebook last year.
Wilders has argued the Koran, which he calls a "fascist book", should be outlawed. He has called for a block on new mosques and claimed Islam was the "biggest threat to our freedom and our civilization".
Labour home secretary Jacqui Smith blocked Wilders from entering the UK in 2009, a decision that was overturned.
Wilders wrote a book last year, entitled Marked for Death: Islam's War Against the West and Me. This tome prompted Thackeray's Facebook posting: "Geert is great.. (peace be upon him … lol) … and so is this eye-opener of a book!"
On the same social media site, Thackeray also blasted Monckton's criticisms of Ukip.
"It would have been more gracious if my old mate Christopher had silently vanished up the Orinoco instead of this undignified defacation [sic]. So let me assure you Ukip Scotland is most definitely NOT wiped out and once I've restructured it will be an even more serious force to reckon with."
A Ukip source said: "It is clear Thackeray's views mean he should not be not interim chair of the Scottish party."
Thackeray was the party's candidate in a council by-election in Glasgow last week. He came fourth, ahead of the LibDems and Scottish Greens. He has also been a director of several firms.
Patricia Ferguson, Scottish Labour's external affairs spokesperson, said: "This is a strange and unwelcome choice of political inspiration even for a senior Ukip official … When we are celebrating a world leader in Nelson Mandela who brought hope to us all, the politics of division and grievance that we see from Ukip look even more out of place."
An SNP spokesperson said: "These are appalling views. The people of Scotland have a proud tradition of supporting justice internationally and opposing racism. Ukip's sorry record of intolerance and bigotry have no place here."
Thackeray could not be reached.