Cussen was admitted to the
Victorian Bar to practice as a
barrister in September of that year. He continued to play cricket, and was a member of the Victorian Bar XI. In 1890, he was appointed as a lecturer in law at the University of Melbourne. Also in that year, he married Johanna Bevan, with whom he would have six sons and a daughter. On 19 March 1906, Cussen was appointed a Judge of the Supreme Court of Victoria. He was widely regarded as an excellent judge. Sir
Owen Dixon, himself regarded as Australia's foremost judge, once described Cussen as "the greatest of all judges." In 1921, he was
knighted for his services as a Judge in the Supreme Court of Victoria. Cussen conducted two consolidations of all the Acts of the
Parliament of Victoria, the first in 1915 and the second in 1928. Consolidation involves compiling all amendments of a particular act into one document. In 1922, Cussen drafted the bill for the
Imperial Acts Application Act 1922, which set out which laws of the
Parliament of the United Kingdom were in force in Victoria. The Act, along with the 1928 version of the consolidated acts, set out every piece of legislation in force in the state at the time in a central location. Cussen was knighted in 1922 in recognition of this effort, in addition to his work as a judge. He continued to sit on the bench in 1924 and again later in 1931–1932, serving as Acting
Chief Justice of Victoria. Aside from his legal work, Cussen was involved in the public life of Victoria. Cussen was elected president of the
Melbourne Cricket Club in 1907, a position he would hold until his death. Cussen remains the longest-serving president of the club. In 1916, Cussen had been made a trustee of the
State Library of Victoria, the
Victorian Museum, and the
National Gallery of Victoria, then run by a single board of trustees, and in 1928 he was made President of the board. ==Legacy==