[3] Hall spent two years teaching mathematics and science at the Eastern Goldfields Senior High School in Kalgoorlie, before taking up a lecturing position at Leederville Technical College in Perth.
[3] After decades of working in fisheries science, Hall submitted his PhD thesis at Murdoch University in 2000, and formally graduated the following year.
[3] In the early- and mid-1970s, Hall was "one of the few computer-literate staff" in the department's fisheries and wildlife research branches, and undertook much of their data processing and computer programming.
[3] After attending a course by Carl Walters and Ray Hilborn, Hall was inspired to use computer modelling approaches to help assess Australian fisheries stocks.
[3] To help his colleagues develop the skills necessary for these approaches, he presented short courses at fisheries agencies around the country.