He was born at Loy Yang to farmer Norman Willie McInnes and Christina Elizabeth Pentland.
Educated at Tinamba and Maffra, he subsequently studied at Dookie Agricultural College and Melbourne University.
On his return he ran the family property at Tinamba and worked as a civil air pilot, being awarded the Royal Humane Society silver medal in 1947 for his role in an air rescue.
The flight in an RAF Sabre Jet took place at North Luffenham in England when McInnes was a Flight Lieutenant in the City of Melbourne Squadron of the Australian Citizens Air Force.
In 1973 he was elected to the Victorian Legislative Assembly as the Country Party member for Gippsland South.