Jake is the symbolic (and later adopted) son of Roland. He is originally from New York, circa 1977, but dies at the hands of Jack Mort (who Jake initially sees as Walter) and ends up in Roland's world as a result. Jake's given name is John, but he prefers to be known by Jake, and is called "'Bama" by his house-keeper only. They travel together in pursuit of the Man in Black, developing a strong bond along the way. However, in order to reach the Man in Black, Roland let him fall to his death.

The eleven-year-old boy Roland left to die reappears in The Waste Lands due to a paradox. Since Roland (in The Drawing of the Three) prevented Mort from shoving Jake into traffic, he never died, therefore he never appeared in Mid-World and was never left to die under the mountains. Jake and Roland, however, can remember both timelines, and the knowledge is slowly driving them insane.

In the first half of The Waste Lands, Roland's ka-tet figure out a way to draw Jake into Mid-world where he belongs (and thus finishes the real Drawing of the Three). Eddie is driven to whittle a key out of wood as they approach a Speaking Ring, where Eddie draws another door into the ground, this one guarded by an invisible demon. Susannah distracts the demon by allowing it to copulate with her, while Eddie perfects the key and opens the door. On the other side, Jake has been led to an abandoned house (by a past-version of Eddie himself) filled with evil spirits and a horrendous gate-keeper, but fights through them (with a bit of timely assistance from Roland) to reach the door. Once in Mid-World again, Roland's and Jake's memories are merged and their descent into insanity abated. Unfortunately, Susannah will pay the price for her distraction of the spirit.

While crossing the desolate city of Lud, Roland promises to come for Jake, despite it appearing that he may have to sacrifice Jake again to ensure their safe passage. Despite the danger, he rescues Jake, reaffirming the father-son bond that has grown between them. Like Eddie and Susannah, Jake shows amazing aptitude to the way of a gunslinger.

Jake is the second member of the ka-tet to die when he sacrifices himself to save Stephen King (a character in his own series) from certain death by putting himself between King and the van meant to take his life. An alternate version of Jake is encountered later by Susannah Dean.

Roland also notes that Jake strongly resembles Alain, another gunslinger, in using a psychic skill referred to as the "touch". Alain is described mostly as his time with Roland as a teen in Wizard and Glass.