Walker, George, 1618–90, Irish Anglican clergyman and commander. As joint governor of Londonderry (now Derry) during the siege (1689) of that city by the army of the deposed James II, Walker roused the people by his courage and inspiring sermons and was able to hold the city for 105 days until it was relieved. He received the thanks of Parliament, was given £5,000 by William III for the citizens of Londonderry, and was designated bishop of Derry. He published A True Account of the Siege of Londonderry (1689) and, in answer to charges of self-seeking, a Vindication (1690). Walker was killed in the battle of the Boyne.