He graduated from the school as captain in 1859 and then became a colleague of Samuel Griffith from 1860 to 1862 at the University of Sydney, where he was a scholar and earned his M.A.

Mein later served as private secretary to the Attorney-General of New South Wales but relocated to Queensland in 1867, where he became a solicitor of the Supreme Court three years later.

In June 1884, Mein assumed office in the First Griffith Ministry, resuming his former position as Postmaster-General, which he exchanged in the following January for the newly created role of Secretary for Public Instruction.

In April 1885, Mr. Mein resigned from Parliament and the Ministry and was appointed a Judge of the Supreme Court following the death of Mr. Justice Pring.

[3] Mr. Justice Mein died on 30 June 1890 in Elizabeth Bay, New South Wales from kidney disease.