 Rooker was made a Personal Chamberlain of the Pope, advancing his title to Monsignor.Monsignor Frederick Rooker was appointed Bishop of Jaro, on 12 June 1903.He was consecrated by Sebastiano Cardinal Martinelli, O.E.S.A, Cardinal-Priest of the Basilica of Sant'Agostino, Rome and who was his former Superior at the Apostolic Delegation in Washington D.C., on 14 June 1903.