He served two brief terms as Solicitor General for Scotland and in 1874 was appointed a Senator of the College of Justice.
[1] He served as an Advocate Depute, a Crown prosecutor in the High Court of Justiciary, from 1858 to 1859 and 1866 to 1867, before being appointed Solicitor General for Scotland, the country's junior Law Officer, in 1867 in the Conservative government of the Earl of Derby.
Millar only held the office until February 1868, when the Earl of Derby was replaced as Prime Minister by Benjamin Disraeli.
He returned to the office of Solicitor General briefly in 1874, again under Edward Gordon as Lord Advocate, before being appointed a Senator of the College of Justice, a judge of the Court of Session, the same year.
The grave lies facing west onto the western path neat the north-west entrance.