Cheika, too, is contracted until the end of 2019.
And while he is not looking that far ahead, Larkham said running the Wallabies one day was a professional goal of all top coaches.
"Everyone wants to aspire to be the best in their position, and the head coach of the Wallabies is certainly the top role in Australia," he said.
"That's a long way down the track. I haven't really thought about it too much. I think as a coach you have aspirations at the top."
Larkham said he would put all his focus into the Spring Tour and then achieving success for the Brumbies in 2017, and only then would he start to think about where he was headed after the 2019 World Cup.
The decision to leave the Brumbies, he said, was tough.
"I have been with the Brumbies for 20 years or so ... and it was a really difficult decision in terms of that," he said.
"I know the Brumbies are in a good place at the moment, and the beauty of this role is I can still be based in Canberra so I will still have a strong connection with the Brumbies.
"The quality of time I have at home will be better than the one I have at the moment. Doing both jobs is very difficult in terms of time constraints."
The Brumbies, who are also still looking for a permanent CEO, said they have already begun their search for a new coach.
Larkham's assistant Dan McKellar, who also coaches the UC Vikings in the NRC, has been groomed for the job and is seen as a front runner.
But the Saturday Telegraph understands Matt O'Connor - who previously played and coached at the Brumbies - is also in the mix, and successful NRC coaches Simon Cron and Darren Coleman are also rising stars of the Australian rugby world.