Former KiwiRail chief executive Peter Reidy is returning to the job after nearly four years heading Fletcher Construction.
Reidy was chief executive of the state-owned enterprise from 2014 to 2018.
KiwiRail chair David McLean said Reidy stood out as a candidate for his "strong, demonstrated leadership ability" and his mana, experience and commercial acumen would be invaluable in leading KiwiRail's transition to financial sustainability.
"KiwiRail is busy delivering a vital programme of $8 billion of Government investment, redressing years of decline. Alongside a Government commitment to invest in the national rail network on an on-going basis, the company is pursuing a strategy which will see it run its 'above rail' freight and passenger operations and Interislander ferries in a commercially successful way."
KiwiRail needed a leader who could hit the ground running, McLean said.