Following his return to Australia, Robertson was embroiled in a landmark High Court tax case, which contested his income in Britain.
Ironically, it was his close friend Justice Owen Dixon who fined Robertson, and arranged for him to help amend the loophole in the Commonwealth tax laws.
Afterwards it is rumored Robertson was satirically made to play left-handed (his non-preferred) against Dixon in a round of golf, which being ambidextrous he still won.
In his later years and up until his death, Robertson was a Victorian representative, and first chairman of the Melbourne branch, of the Liberal Party of Australia, and a confidant of Robert Menzies.
An avid adventurer and sportsman, Robertson was known to host raucous hunting and fishing parties and bush dances at his beloved Mallacoota estate, Mirrabooka.