Frank Langdon is a senior resident, Dr. Robby's right-hand man. He is married to Abby and they have two children under the age of four. He doesn't spend much time with them due to his demanding schedule as an ER doctor at Pittsburgh Trauma Medical Hospital.

He is a good doctor; he knows what he's doing, although he can sometimes be a bit self-centered, a jokester, and annoying to his colleagues. He was caught by a medical student, Trinity Santos, accusing him of stealing medicine from patients.