He also served as Erasmus Smith's Professor of Mathematics from 1799 to 1800 and the Church of Ireland Bishop of Dromore for a few days before he died in 1811.
[3] Hall resigned his fellowship and professorship in 1800, and on 25 February of that year was presented by his college to the rectory of Ardstraw in the diocese of Derry.
In 1806, he returned to Trinity College, having been appointed to the provostship by patent dated 22 January, and held that office until his promotion, on 13 November 1811, to the bishopric of Dromore.
He was consecrated in the college chapel on the 17th of the same month but died on the 23rd in the Provost's House, from which he had not had time to move.
He was buried in the Chapel of Trinity College, where a monument with a Latin inscription to his memory was erected by his niece, Margaret Stack.