From 1841 to 1845, he was Advocate Depute, and from 1845 to 1852 Sheriff of Orkney and Shetland. He became Solicitor General for Scotland in 1853, being succeeded by Robert Handyside, Lord Handyside. He served as a judge of the Court of Session from 1853 to 1858. From 1858 to his death, he was Lord of Justiciary, Scotland's supreme criminal court. Neaves lived the majority of his life in Edinburgh, but when associated with the Justiciary Court, he travelled to Glasgow thrice yearly and Lord Neaves (although elderly and almost without hearing capability by the 1875) acquired a reputation in Glasgow as a man of justice and evenness.