As a young child, Tem and his brother, Cal Barkwater, were sold into slavery in the Deepwoods, and were used as tarry vine bait on numerous occasions. Many years later, Cal managed to escape, and the enraged merchant who owned the pair thought Tem had helped him get away. Quint rescued Tem from the merchant, and he took up a position aboard the Galerider, under the tutelage of the harpooneer, Steg Jambles. Tem later served under Quint on his sky ship, the Stormchaser.
AdulthoodDuring the event of Stormchaser, Tem wandered off into the Twilight Woods upon seeing a hallucination of his brother. He later got out of the woods when he was captured by a band of shrykes and put on sale in a Deepwoods slave market, which makes him one of the very few death-cheaters. Tem managed to escape, and journeyed to the Free Glades, where he was united with his nephew, Shem Barkwater, and Shem's wife, Keris, who was also the grandaughter of Quint. He lived with them for several years, and after they were killed by slavers in the Deepwoods, he continued to live in the Free Glades. He frequented the New Bloodoak Tavern, and became silent and withdrawn. The locals knew him as 'The Mire Pirate'. During the events of Freeglader, Tem met his great-nephew, Rook, and told him the story of his past.
Throughout his life, Tem Barkwater was fiercely loyal to his family and to his fellow Sky Pirates. When his slave master punished him for the escape of his brother, Tem did not care about his own injuries because of his happiness that Cal had gotten away.