Barnaby Joyce says he hopes to return as deputy prime minister a better person after defeating Michael McCormack for the Nationals leadership.
Mr Joyce was elected Nationals leader in a partyroom ballot in Canberra on Monday, returning to the job he lost more than three years ago.
The NSW MP quit in 2018 after scandals stemming from his affair with a staffer who has now given birth to the couple's two children, as well as sexual harassment allegations he strongly denies.
Nationals MPs Michelle Landry and Anne Webster expressed concern Mr Joyce's history could damage the party's standing with female voters.
Mr Joyce said he wouldn't tell any group of voters what to think about him.
"I acknowledge my faults. I resigned as I should and I did," he told reporters at Parliament House.
"I've spent three years on the backbench and I hope I come back a better person."
Mr McCormack refused to be drawn on what Mr Joyce's return would mean for the Nationals support among women.
"I'm a man in regional Australia so you'd have to ask women in regional Australia," Mr McCormack said.
"He's got more numbers than me this morning so good luck to him."
Mr McCormack made a dignified exit, vowing he would be a team player and immediately living up to that as he faced the music during a bizarre Question Time.
With Mr Joyce not being sworn in until Tuesday and Scott Morrison attending parliament virtually, Mr McCormack fielded questions from the prime minister's usual chair.
There was gallows humour as he answered a Dorothy Dixer about government spending in regional Australia.
"Numbers have not been my friend today, but these numbers are very enlightening," he said
Mr McCormack finishes as the longest-serving Nationals leader since John Anderson led the party for almost six years during the Howard government.
"Que sera sera," he told the chamber as he finished Question Time, sparking a round of applause from across the political divide.
Mr Joyce denied waging a three-year campaign to return to the leadership.
"If I thought it was going to happen, I would have brought my hat," he said, appearing without his Akubra.
Speculation grew over the weekend Mr McCormack was in danger of a second spill against his leadership after unnamed MPs briefed journalists.
"For the sake of good government - and not just good government - for the people of Australia, if you are going to say something, have the guts and gumption to put your name to it," Mr McCormack told reporters.
"Don't background against your colleagues. It's not good for the parliament. It's not good for democracy."
Scott Morrison paid tribute to Mr McCormack while saying the coalition would remain a strong partnership.
The prime minister will have to navigate a new dynamic with Mr Joyce widely regarded as a more combative force within the coalition.
The change in Nationals leadership could have other implications for the government with the junior coalition partner set for a ministerial reshuffle.
Bridget McKenzie, who quit after the so-called sports rorts saga, is expected to return to cabinet.
Mr McCormack is weighing up his future in politics but noted he had been pre-selected to recontest his NSW seat of Riverina.
Mr Joyce failed to topple Mr McCormack at his last attempt in February last year but prevailed at his second crack.
Australian Associated Press