He first appears on record in 1478 as the rector of the church of Tyningham, and is called a clerk of the diocese of Brechin.
[2] On 22 October 1483, he was selected to be Bishop of Dunkeld, despite the election of Alexander Inglis on 17 September the same year.
[5] According to Alexander Myln, in his 16th century Vitae Dunkeldensis ecclesiae episcoporum ("Lives of the Bishops of Dunkeld"), Brown used the opportunity to become friendly with many of the cardinals, including Roderick Borgia, papal vice-chancellor and Bishop of Porto, the future Pope Alexander VI.
In May 1485 the Parliament of Scotland supplicated the Pope to reverse his decision in favour of Alexander Inglis.
Alexander Myln attributes reconstruction of the diocese to Brown's episcopate, namely in the creation of four rural deans.