Complex sentence: From 1956 to 1966, Warren III was Director of the Administrative Office of the United States Courts, by appointment of Chief Justice Earl Warren, whom Warren III had served under in the California Attorney General's Office.
Split into simpler sentences: From 1956 to 1966, Warren III was Director of the Administrative Office of the United States Courts. He was appointed by Chief Justice Earl Warren, whom Warren III had served under in the California Attorney General's Office.