Simpson returned to Australia, he had a productive period in the Sheffield Shield for Western Australia, rectifying his prior problem of not capitalising on his starts. On the advice of Harvey, he reinvented himself as an opening batsman in an attempt to exploit the opportunity opened by the retirement of Test opener Jimmy Burke. At the start of the 1959–60 Australian season, he scored 98 and took a total of 2/77 in a drawn match against Victoria. In the next match, Simpson broke through for his maiden double-century, posting 236 not out in Western Australia's 4/487 declared against New South Wales. In contrast, Simpson's native state could manage a match total of only 382 in an innings defeat, as he took 1/17 and 5/45.