"We were planning for victory right up until the last minute, so it was incredibly disappointing to have lost," Liddell told the Herald on Sunday. "The past five months of the job were about as intense as it gets, but you have to be philosophical in defeat and move on."
The high-flyer is a former director of the New Zealand Rugby Union and was chief executive of forest products firm Carter Holt Harvey.
In the US, he was a senior vice-president and chief financial officer at Microsoft, before becoming financial chief at General Motors. Liddell abruptly quit GM last year, amid speculation he had been passed over for the top job. He said he volunteered to work for Romney last year after agreeing with his platform of a smaller government and increased economic growth.
"I was regularly involved with Mitt early on in the campaign, but he went on the road and I went to Washington to run the transitional team," Liddell said. "Had Mitt won, I would have been working very closely with him organising the White House and his government."
Liddell, who visits New Zealand about twice a year, said he had made no firm decisions about his next career move. "I went into the campaign with no Plan B if we lost, that is how confident I was we would win."
Meanwhile, US reports said when Romney's staffers tried to take cabs home after his election-night concession speech, they discovered their campaign credit cards had been cancelled during the night.
