Byrnes continued his private law practice and participated in two major Supreme Court of Queensland cases. In the "Queensland Investment Co." v. "Grimley" case, Byrnes successful conduct of the defence was praised widely. In the John Robb arbitration case of 1892, praise for Byrnes skill was accompanied by public objection to the high fees paid to Samuel Griffith as leading counsel and to Byrnes as one of his assistants. In 1895 and 1897, Byrnes represented Queensland at meetings of the Federal Council of Australasia.