Steamboat Bill is William Canfield (Ernest Torrence), the larger-than-life owner of the stern-wheeler 'Stonewall Jackson' which he has operated successfully for many years with his first (and only) mate played by Tom Lewis. Almost all of the town is owned by entrepreneur and businessman J.J. King who has now introduced his own stern-wheeler, a pleasure palace named 'King', to take all the trade and drive Stonewall Jackson off the river and Steamboat Bill out of business. William Canfield, Jr. (Buster Keaton), has been at college in Boston but a telegram informs Steamboat Bill that the son he has not seen since a baby is going to visit. Expecting a giant of a youth to appear from the train, Steamboat Bill and his mate are amused and perplexed to find the small and skinny Keaton appear at the station. Steamboat Bill Jr. gets kitted out to work on the Stonewall Jackson and then discovers that he is a college friend of Kitty, the pretty daughter of no other than J.J. King! King contrives to get Stonewall Jackson condemned as being unsafe but, during an enormous cyclone which destroys much of the town and sees Keaton performing numerous amazing stunts, the 'King' sinks but the old boat survives and rescues Steamboat Bill from a floating jailhouse, and King and his daughter from imminent disaster - all ending happily for the young couple.