he was son of an english clergyman, james dickson, who was dean of down from 1768 till 1787. he was educated at eton college, where he formed a lifelong friendship with charles james fox and several of fox's nearest friends, one of whom, lord robert spencer, became his executor. he entered hertford college, oxford, graduating b.a. 1767, m.a. 1770, and d.d. by diploma 1784.