Lacey was educated at University College, Oxford, where he was a mature commoner, then Fellow, and subsequently Master of the College from 1398 until around 1401.

[3] In 1401, Lacey was appointed Canon of the ninth stall at St George's Chapel, Windsor Castle, a position he held until 1417.

[4] Around 1414, Lacey was appointed Dean of the Chapel Royal, accompanying King Henry V to the Battle of Agincourt in 1415.

[5] He was elected to the see of Hereford between 21 January and 17 February 1417 and consecrated on 18 April 1417.

[7] While bishop at Exeter, Lacey promoted the cult of the Archangel Raphael, proclaiming the feast in his diocese in 1443, and working throughout England to institute the cult.