ABC managing director David Anderson will depart the public broadcaster after his leadership came under internal scrutiny.
Mr Anderson was appointed to a second term in the role in 2023 but will step down once a replacement is found.
He said he expected to remain in the role until at least the start of 2025.
Unionised ABC staff members passed a vote of no confidence in Mr Anderson in January for "failing to defend the integrity of the ABC and its staff from outside attacks".
The ABC board rejected the union's claim and passed a unanimous vote of confidence in Mr Anderson.
In a note to all ABC staff on Thursday, Mr Anderson said he was grateful to new chair Kim Williams and the board for their support and efforts to persuade him to stay on for a full second term.
"Their unabashed enthusiasm for the importance and future of the corporation makes this decision easier," he said.
"I am confident the timing is right for both me and the ABC."
Mr Williams, a former News Limited chief executive who took over from Ita Buttrose as chair in March, said the delayed resignation would ensure a smooth transition and praised Mr Anderson.
"I have to say my admiration for him and his commitment to the ABC is undiminished and my respect grows ever greater," he said.
"He is an exemplary executive in many ways."
The recruitment process will begin in due course, the ABC said.
