Marty Hamilton was a neurologist from Los Angeles who appeared in the episode DNR. Hamilton was the primary care physician for John Henry Giles. Hamilton was Eric Foreman's supervisor during Foreman's residency and was his boss immediately before Foreman started working for Gregory House. He was portrayed by actor David Conrad.
Giles, who had collapsed during a visit to New York City was being treated by Foreman at PPTH at Hamilton's request, however House wanted the case. Cuddy told House that they were only treating John Henry for pneumonia, since his paralysis was treated by Hamilton. Hamilton had already diagnosed the paralysis as an effect of ALS, which would explain the pneumonia. House does not agree with this diagnosis and sought other explanations for the paralysis.
House violated a DNR order and Foreman called Hamilton who was flying in from Los Angeles. Hamilton, who only called House by his first name. He insisted he had properly diagnosed John Henry. House reminded him of the error rate that occurs in those blood tests and biopsies. Hamilton wanted to respect the patient's wishes and discontinue life support for John Henry.
Hamilton then offered Foreman a job that paid three times what made with House and included many other perks. Foreman mentioned the offer to Cameron and Chase, who pointed out that they do not hold their jobs for merely the money. They also do not hate House like Foreman does. House and Hamilton had different theories about John Henry's condition, House told Foreman to take the job if he was a better doctor.
However, after they started withdrawing treatment from John Henry, his condition changed so drastically that Dr. Hamilton came to House to ask for an explanation of what had happened. House traced John Henry's condition to an arteriovenous malformation, something that even Hamilton had considered, but they had both missed it as it was hiding behind edema. They only found it after giving John Henry steroids for another condition they thought he had. The malformation was corrected with surgery.