Professor Aronnax is the main character and narrator of the book. He is a 40-year-old Frenchman who works as an Assistant Professor at the Museum of Natural History in Paris. He previously published a two-volume work called Mysteries of the Great Submarine Grounds, which Captain Nemo has a copy of on board the Nautilus. Aronnax has an adventurous spirit, and travels to various locations to study natural history with his servant Conseil and a menagerie that includes a wild pig. He passes his time on the Nautilus studying marine life, and finds the work fulfilling until Captain Nemo’s rage compromises Professor Aronnax’s morals. Up to that point, Aronnax feels admiration and respect for Captain Nemo, judging him to be capable, intelligent, and of “unparalleled courage” (131). Professor Aronnax maintains a loyal friendship with Conseil and Ned Land—his two companions on the Nautilus—which helps them to survive their escape from the ship.

Conseil is Professor Aronnax’s loyal servant who will do anything for his master, including putting Professor Aronnax’s life above his own. He is a 30-year-old “Flemish boy” (9), who for 10 years has accompanied Professor Aronnax on his journeys, helping him with his research. Professor Aronnax describes Conseil as “quick with his hands” (10), in excellent health, and always obliging.