In House M.D., James Wilson leads the Department of Oncology at Princeton-Plainsboro.
Wilson is an oncologist whose work centers on patients with cancer and on difficult decisions about treatment, prognosis, and comfort. His specialty contrasts with House's diagnostic medicine, but the two departments frequently overlap because unexplained symptoms can result from malignancy or treatment complications.
The character is played by Robert Sean Leonard. Wilson often acts as House's moral and emotional counterweight, yet the series does not portray him as simply conventional or flawless. His personal life includes multiple marriages, complicated relationships, and choices shaped by his deep identification with his patients.
The department title matters because House M.D. includes several senior physicians with different roles. Lisa Cuddy is the hospital administrator, while Gregory House heads diagnostics. Eric Foreman eventually becomes a senior hospital leader, but he is not the oncologist who heads the department during the central period of the show. Wilson's specialty remains one of the clearest identifiers of his character.