The John Lawrence Sullivan papers contain correspondence, writings, newspaper clippings, ephemera, photographs, and artifacts including a crystal bowl and wooden brush engraved with Sullivan's initials, a printing plate featuring Sullivan, and an autograph book. Correspondence makes up the bulk of the collection and dates from the 1890s to 1912. Letters relate mainly to Sullivan's career on the stage but also include correspondence with boxers such as Ike Weir and Martin Flaherty. Other notable correspondents include Theodore Roosevelt and his secretary, William Loeb, Jr. Writings include a poem by Sullivan and three articles related to Sullivan's boxing and stage careers by an unidentifed author. Newspaper clippings date after Sullivan's death and were most likely compiled by his nephew and heir, Arthur Lennon.