He is the kind-hearted country doctor of a small town who is known for using common sense to cure the residents of his town rather than simply use medicine. In one instance he was able to cure an elderly lady by bringing her son, Jamison, the Lawyer, over which cured her of her illness. He even humors a child whose doll fell in a well by retrieving it and performing CPR.
He fell in love with the Sick-Little-Well-Girl when he first saw her in town and went to her house to help cure her when asked by the Lawyer who was friends with her father. He inspects the girl but when he was inspecting her eyes, he accidentally kissed her when he lost his balance. Ludwig, threatened by Jack, takes advantage and asks the Sick-Little-Well-Girl's father to get rid of Jack or he'd resign. Jack is dismissed from her case, but is allowed to stay in the house until morning.
The Sick-Little-Well-Girl, who returned Doctor Jack's feelings sneaks to see him one last time when a gunshot is heard. Everyone in the house learn that a crazed convict, Lumpy Logan was seen near the premise. The knowledge excites the Sick-Little-Well-Girl, which makes Doctor Jack realize she had never known excitement. Ludwig tries to make it look like she was having a relapse so Jack realizes Ludwig was a con artist keeping her seemingly ill to get money from her father. Jack tries to convince her father that excitement was what his daughter needed but Ludwig says that if the father sided with Jack, he'd resign. Due to his charisma, the father sides with Ludwig.
Still determined to help the Sick-Little-Well-Girl, Jack dresses himself up like Lumpy Logan and runs around the house switching between roles for full effect. The Sick-Little-Well-Girl joins in chasing "Lumpy Logan" and eventually learns that Doctor Jack was pretending to be Lumpy Logan in order to cure her. She herself dresses up and exposes the whole thing to her father, proving Jack was helping her. Seeing her so full of life and energy finally makes her father realize Ludwig was nothing but a fraud and kicks him out, while Doctor Jack and the Sick-Little-Well-Girl become a couple.