Alexander acts in a broad range of commercial and public law disputes with a particular focus on matters in federal jurisdiction.

In commercial areas, he has expertise in competition (including access regulation) and consumer law, insurance, employment and discrimination. He has been led in major litigation in all those fields, and regularly appears unled in commercial disputes in these areas.

In public law, Alexander has appeared in and advised on numerous matters raising constitutional issues, including on several occasions in the High Court, as well as in native title. He is regularly briefed in judicial review proceedings in the Federal Court, the general federal law jurisdiction of the Federal Circuit and Family Court, and the New South Wales Supreme Court.