At Harvard, Crowninshield kept a daily diary through his junior and senior years, which was published in 1941 by his son Francis, under the title "A Private Journal, 1856–1858". It records that he was captain of the rowing team; handled most of his classes with ease, with the exception of Logic which he called "that cursed nonsense"; was president, Learoyd Director, and Abercrombie Treasurer of the Glee Club; was a member of the Porcellian Club and Pierian Sodality; was treasurer of the Hasty Pudding; sang in the choir; and played the 'cello. He resided, in 1856, at Number 9 Hollis Hall. His diary records many activities, from visiting old friends through attending drawing courses and music lessons; going to dances, theatres, and concerts; playing billiards at Ripley's; and spending the evening in Parker's Restaurant; to spending a whole day making a model boat.