Many European leaders greeted the property mogul’s shock success with barely-disguised alarm - although Theresa May said she was looking forward to working with him.
Mr Duncan Smith argued that Tuesday’s result could “reinvigorate” the so-called ‘special relationship’ between the UK and America.
During the campaign Dan Micco, the billionaire’s trade advisor, suggested the post-Brexit UK could be first in line for a trade deal with the US under a Trump presidency.
His remarks contrasted markedly with President Obama’s warning ahead of the EU referendum that Brexit would put the UK “at the back of the queue” for a trade agreement.
Writing on the ConservativeHome website today, Mr Duncan Smith criticised the Obama administration’s attitude towards Britain and said Mr Trump offered the potential to renew US-UK ties.
He said: "For the last eight years President Obama made it abundantly clear that he did not consider the UK as any more important in his international relations than any other country, particularly Germany and the EU itself. The so called ‘special relationship wasn’t very special and not much of a relationship.
"In the UK, we have a choice. We can, like so many others, indulge ourselves in an orgy of complaint about the result – we have already seen that kind of behaviour over the Brexit result. Or we can choose to engage with the new administration in a positive way…
“We should seize this opportunity to engage the new administration and remind them of our enduring friendship in good times and in bad. A positive tone of support and assistance will reinvigorate a relationship which has the potential to help us both.”