Barnaby Joyce says he will resign as Australia's deputy prime minister following a politically damaging saga that began with his affair with a former staffer.
Mr Joyce said he would step down on Monday as leader of the Nationals, the junior government partner.
Mr Joyce had resisted calls to quit amid questions over whether he had breached ministerial rules.
He called his decision on Friday a "circuit-breaker".
"This current cacophony of issues has to be put aside," he told reporters.
Mr Joyce is perhaps best-known for once threatening to kill Johnny Depp's dogs over a quarantine violation, and for briefly losing his job over his New Zealand dual citizenship last year.
On Friday, Prime Minister Malcolm Turnbull thanked Mr Joyce for being a "a fierce advocate for rural and regional Australia".
The political scrutiny of Mr Joyce has dominated Australian headlines for more than two weeks.
Last week, Mr Turnbull publicly criticised Mr Joyce's "shocking error of judgement" and said ministers would be banned from having sex with their staff.
Mr Joyce responded by calling Mr Turnbull's comments "inept" and "unnecessary", but insisted the pair could still work together.
Joyce's authority eroded
Hywel Griffith, BBC News Sydney correspondent
Fighting a barrage of bad headlines, Barnaby Joyce knew his position had become untenable.
Sometimes strenuous denials and combative rebuttals just aren't enough to win back the news agenda.
More importantly, they didn't succeed in maintaining the trust and credibility he has enjoyed for most of his career.
Although Mr Joyce is known as a battler who enjoys a big personal vote, support amongst his colleagues had started to ebb away.
And so, rather than face the potential humiliation of a leadership contest, Mr Joyce took matters into his own hands and put himself on the backbench.
On Friday, Mr Joyce again insisted that his relationship with his former media adviser, Vikki Campion, had not resulted in any breaches of standards at the time.
The veteran MP faced scrutiny over the timing of two jobs offered to Ms Campion within his party last year, and whether he sought a gift of free housing from a businessman.
He has also vigorously denied a sexual harassment complaint that was made against him by another woman.