McLernon's documented career is rooted in Western Australia, the largest Australian state by area, whose capital is Perth. He studied law at the University of Western Australia and later worked in the state's legal profession before moving into corporate and finance roles.
McLernon studied law at the University of Western Australia, the state's first university. It was established in 1911 by an act of the Western Australian Parliament, opened to 184 students in 1913 with the faculties of engineering, science and arts, and added a Faculty of Law in 1927.
His legal training led to his admission to the Western Australian bar in 1972, the point at which he entered practice as a barrister. He holds a Bachelor of Laws degree from the university.
After his legal studies, McLernon worked as a Crown prosecutor for about eight years. Crown prosecutors conduct criminal prosecutions on behalf of the state, and this public role preceded his later work in private practice.
He then practised as a barrister at the independent bar for a further nine years, a branch of the profession in which barristers work independently of law firms. In 1985 he acted as counsel in an appeal against the conviction of Brian Mickleberg arising from the Perth Mint swindle, a case he later described as a long battle that Mickleberg eventually won.
He subsequently joined Clayton Utz for three years as a litigation partner. Clayton Utz, established in 1833, is one of Australia's oldest and largest full-service commercial law firms, with offices in Sydney, Brisbane, Canberra, Darwin, Melbourne and Perth. In 1988 he retired from legal practice, citing in an interview the length, cost and technical character of litigation and its potential for misuse as reasons for leaving courtroom work.
McLernon is also recorded as a partner at Robinson Cox. From 1996 to 2001 he was managing director of the Hill Group of companies, which operated in finance, mining, property, insurance and investment in Australia.
In 2001 he promoted the listing of Insolvency Management Fund Limited on the Australian Securities Exchange. Litigation funders finance legal claims in exchange for a share of any recovery, and the company that became IMF Bentham listed in 2001 to promote transparency in what was then a new industry in Australia. IMF was later described as Australia's largest litigation funder and a pioneer of the global industry. McLernon was the inaugural managing director from 2001 to 2004 and returned as managing director on 18 March 2009, retiring from that role on 5 January 2015. He has been an executive director of IMF Bentham since December 2001 and oversees its special projects.
McLernon introduced the secondary life insurance market into Australia through the Capital Life Exchange in 1988. The secondary market allows holders of life insurance policies to sell them to investors before maturity, offering an alternative to surrendering a policy to the insurer.
He pioneered the funding of large-scale litigation in Australia through McLernon Group Limited. This external financing of legal claims later developed into a substantial industry in Australia and internationally.
He led the establishment of IMF (Australia), later IMF Bentham, and promoted the 2001 listing of Insolvency Management Fund Limited on the Australian Securities Exchange. The company's listing was intended to promote transparency in what was then a new litigation funding industry, and the company describes itself as one of the earliest publicly listed litigation funders.
