Mr McCormack beat out New England MP Barnaby Joyce in a vote for leadership of the National Party and the Deputy Prime Minister role. Water Resources Minister David Littleproud will be the new deputy leader of the party.
Mr Coulton said he was "very pleased" with the results of the spill.
"I think both choices are very good. I'm a big supporter of Michael, and David will do a good job as a replacement for Bridget McKenzie," he said.
"This is not new for Michael. He'll continue on and David obviously had a big job with agriculture and then dealing with the fires and the drought, so although he's not been in parliament as long I think they'll be a good team.
"It has been an unfortunate distraction at the start of the year, but we have been reassured by all members of the party room that they are united and focused."
The spill comes after the resignation of Ms McKenzie on the weekend following the "sports rorts" scandal.
The Greens will now be led by Adam Bandt, which was decided upon after former leader Richard Di Natale resigned to spend more time with family.
Mr Coulton said he was always confident Mr McCormack would get the numbers after spending Monday night on the phone calling colleagues, and that the media tried to "pretend that it was a close contest".
"The numbers that are being reported are being made up mischievously by the press gallery," he said.
"There's only two people who know what they were and they are the two whips.
"We're not playing those games and we're getting on with the job."