After that he climbed the ladder at the conservation department before retiring in 2013.
He "failed miserably" at retirement, he said, and returned to work five times.
"I happen to have just been in the right place in the right time to be asked to do these jobs," Ombler said.
He finished his role as All-of-Government Controller in November last year and is now on a five-member panel considering the future of local government in New Zealand.
"It's quite a long project, because there's an awful lot of people to talk to," he said.
The panel is due to make a final report on April 1, 2023. After that Ombler may have more time at his home in Wanaka and with his children and grandchildren.
He was made a companion of the Queen's Service Order (QSO) in 2013, and he feels very honoured by his newest title. Receiving it for public service comes as no surprise.
"I am a committed public servant. I have been a public servant all my career. I haven't said no to requests to help out with important matters."
Being All-of-Government Controller was a tremendous experience, surrounded by absolutely amazing people who worked extraordinarily hard, he said.
It was fascinating, and something he never prepared or applied for. What made it enjoyable was the way the country's "so-called team of five million" responded in the crisis.
Ombler said he doesn't panic in difficult situations, because that response wouldn't help.
"With big tasks like this, I just tackle them one step at a time."
His other post-retirement roles have included being chief executive of the Canterbury Earthquake Recovery Agency and conducting an inquiry into financial irregularities at the Waikato District Health Board.
His years as a ranger at Pipiriki were a long time ago but they were wonderful and important, he said.
"Pipiriki was a tremendous community to be in. It was very supportive and I learned a huge amount about the river and about the people."
He and his then-wife Kathy wrote books about both – books that influenced the formation of Whanganui National Park. He also helped set minimum flows when the river's headwaters were diverted to generate electricity.
He credits getting all those important jobs with his experience, as well as luck.
"I've had quite a long and varied career. I worked in the provinces a lot and worked in Wellington a lot and worked in delivery and policy," he said.