In the This Is Us episode “Last Christmas,” on Christmas Eve the Pearsons (of the past) take little Kate to the hospital with a case of appendicitis. While at the hospital, they discover Dr. K (Gerald McRaney), the OGBYN who delivered the Big Three, is a patient at the hospital and he’s all alone. Meanwhile, in the present, Randall’s birth father William (Ron Cephas) goes to a meeting and reunites with a man from his past, Jesse.
Jesse is portrayed by Denis O’Hare. He’s known for his roles in the films Dallas Buyers Club (Dr. Sevard), The Proposal (Mr. Gilbertson), Milk (John Briggs), J. Edgar (Albert Osborn), and on the TV shows American Horror Story (Spalding), The Good Wife (Judge Charles Abernathy), True Blood (Russell Edgington), and Brothers & Sisters (Travis Marsh), among others. This Is Us airs Tuesdays at 9pm on NBC.