Mr. Morton is an old British sailor marooned on an uninhabited island after a separate shipwreck. He arrives with an Australian Aboriginal boy, TamTam—also called TomTom in some dubs—and becomes a parental figure to him after the boy’s parents were killed by white settlers.

Initially coarse and rude, Mr. Morton complains frequently about the lack of alcohol and once drinks alcohol being used as an antiseptic by Dr. Robinson. His practical, survival-focused nature leads to conflict, such as when he argues for leaving the family’s animals behind during ship construction due to concerns over limited space, food, and the uncertainty of the voyage.

He orchestrates a distraction to steal a rifle, a magnifying lens, and other items from the Robinsons’ treehouse, then departs the island alone without informing TamTam. He later returns and explains his sudden departure: he had attempted a dangerous solo canoe voyage across the ocean hoping to find help and secure rescue for the Robinsons and TamTam.

Mr. Morton possesses extensive nautical knowledge. He correctly estimates the island’s coordinates and is the first to identify frequent earthquakes as signs of volcanic activity, deducing the island is unstable and may erupt. This discovery becomes the main motivation for building a seaworthy vessel to reach Australia.

His relationship with the Robinsons is initially strained. Anna Robinson is repelled by his rudeness and his attempt to get the youngest child, Jack, to smoke an improvised cigarette. The oldest son, Franz, also dislikes him. Mr. Morton eventually wins the family’s trust when a letter he wrote requesting rescue is found, revealing his good intentions. He works with the family to build the ship and guides their voyage to Australia.

After the successful journey, he does not remain with the Robinsons in Australia. He finds another ship to work on, and TamTam accompanies him. Their departure coincides with Emily’s journey to England to study medicine.