Bentley never became a college fellow, which would have been the more natural course to an academic career. Instead, he was appointed headmaster of Spalding Grammar School before he was 21 years old. Edward Stillingfleet, the dean of St Paul's Cathedral in London, hired Bentley as tutor to his son. This allowed Bentley to meet eminent scholars, have access to the best private library in England, and become familiar with Dean Stillingfleet. During his six years as tutor, Bentley also made a comprehensive study of Greek and Latin writers, storing up knowledge which he would use later in his scholarship.