"Unfortunately, it didn't make me electorate MP but with a 30-day campaign it was always going to be tough," said Mr Mark, who announced his candidacy in August.
"But, I am hugely grateful that 8000 people expressed their confidence in me, and thought I was the best choice."
In the candidate vote, Mr Mark "won" in his home town of Carterton, achieving 37 per cent of the votes.
Mr Scott achieved 35 per cent, while Labour's Kieran McAnulty achieved 24 per cent.
Back in Parliament, Mr Mark's responsibilities will be on a national scale - but he said he is "not going anywhere", remaining in Wairarapa with partner Christine Tracey.
He plans to keep new MP Mr Scott honest.
"One of my many jobs is to hold him to account.
"I struggle to believe Wairarapa voted in the best person for the job.
"But we've got a new MP now, and he'd better do a good job and represent us well - and I intend to make sure he does."
Mr Mark's parliamentary career means he will resign as Mayor of Carterton, a role he has held for four years.
He said deputy mayor, John Booth, would likely run unopposed to succeed him.
"I didn't think it was possible to do both jobs - but Carterton will be in good hands.
Mr Mark said he is looking forward to representing New Zealand First.
"Our voters have strong concerns about things like the cost of living, low wages, foreign investment and the sales of land.
"There's a strong sense something's not right."
