Clint Eastwood has spoken for the first time in defence of his widely mocked address at the Republican national convention, stating that the "unorthodox" approach of chastising an empty chair went down well with delegates in the hall.

In an interview with his local paper, the Carmel Pine Cone, Eastwood admitted that the decision to use the prop – in which an invisible President Barack Obama was apparently seated, offering the odd inaudible profanity in response to actor's questioning – was a last minute addition to his star turn in Tampa.

But despite a response which was largely negative, Eastwood maintains that it was well-received by Republican leaders as well as rank-and-file members.

The audience were "super enthusiastic", the 82-year-old actor told the Pine Cone. And after the speeches had concluded, Republican presidential nominee Mitt Romney and his running mate Paul Ryan both sought out Eastwood to thank him personally.

"They were very enthusiastic, and we were all laughing," Eastwood said.

His account differs from that reportedly given by Romney's aides in the aftermath of the convention. The New York Times said "baffled" staffers were left pointing fingers at each other over who authorised the shambling performance.

During the actor's slot, an imaginary Obama was berated over the decision to go into Afghanistan, despite it being his predecessor George W Bush who sent troops into the conflict.

Eastwood also alluded to imagined profanities uttered by the silent and invisible president. "What do you want me to tell Romney?" he asked the empty chair, adding: "I can't tell him that. He can't do that to himself."

The crowd laughed, but many others around the country cringed. In the Carmel Pine Cone interview, Eastwood said the address had not been vetted by Republican Party officials, and that the use of a chair was a late addition by the actor himself.

"There was a stool there, and some fella kept asking me if I wanted to sit down," he told the paper in Carmel, the California town where he served as mayor in the 1980s.

"When I saw the stool sitting there, it gave me the idea. I'll just put the stool out there and I'll talk to Mr Obama and ask him why he didn't keep all of the promises he made to everybody."

Eastwood admitted the move was "very unorthodox", but explained that he wasn't much of a public speaker. "I was a mayor, and they're probably thinking I know how to give a speech, but even when I was a mayor I never gave speeches. I gave talks," he said.

As to any criticism resulting from the bizarre convention turn, Eastwood dismissed it as coming "obviously from the left".

He also took the opportunity to sharpen his attack on Obama, describing the president as "the greatest hoax ever perpetrated on the American people".

Eastwood added: "Romney and Ryan would do much better job running the country, and that's what everybody needs to know. I may have irritated a lot of lefties, but I was aiming for people in the middle."