Maxwell was a Rhodes Scholar at Oxford in 1975 and was then called to the Bar as a member of Lincoln's Inn in 1978, practising briefly at the English Bar before returning to Melbourne in 1979. From 1983 he was variously reader for Kenneth Hayne QC, Principal Private Secretary to Gareth Evans (Commonwealth Attorney-General), and reader for Ross Robson QC. He signed the Victorian Bar Roll in 1984 and became a QC in 1998.
Maxwell was the Victorian Legal Aid Commissioner for seven years and also a member of the Board of Liberty Victoria for six years, two of them as President.
He appeared with Julian Burnside QC in the Tampa refugee case, and was then famously but unsuccessfully countersued (as a Board member of Liberty Victoria) by the Commonwealth of Australia for costs.
He reviewed the Occupational Health and Safety Act 1985 for the Victorian government.
Justice Maxwell is married with three children.