He was played by Ken Jenkens.
Serving as chief of medicine since 1985, Dr. Kelso is often seen as an unremorseful sort of man towards both patients and colleagues. Until he retired at will, Kelso was completely desensitized by death and was infamous for his steadfast policy of a lack of insurance meaning the patient had to leave. This stickler attitude that was mainly budget focused rarely ever waned unless he had a personal connection with the patient.
Dr. Kelso had one main enemy and constant thorn in his side was Dr. Perry Cox who after Bob was forced out at age 65 became the interim Chief of medicine for one episode. Upon the short return of Kelso as Chief of Medicne he eventually retired on his own terms but rarely left the hospital much after. This was due to while he was Chief of Medicine having won free muffins for life at the in-hospital Coffee Bucks (a play on the popular real life Starbucks) and that he must have loved the hospital deep down due to the long history he had with it. Another constant antagonist in his own life was Kelso's own wife Enid who he has said was overweight and whiny on multiple occasions. Being that he is no stranger to conflict, Kelso was often (and practically always) accompinied by the spineless lawyer Ted Buckland whom Kelso used for odds and ins beyond legal works that his job called for, which explains why Ted immediately clung to the Janitor as his new leader.
Aside from what he displayed on the job at the hospital, Kelso indeed had a compassionate side. Whether it be for his gay son Harrison or with personal friends he might have brought into the hospital to be cared for like his friend from the park, Maggie. As well as his beloved dog Baxter whom he often seemed to favor over his own wife Enid. Kelso later became a professor after the passing of his wife Enid and made sure to steal his favorite table and chairs from the Coffee Bucks. He later and currently is a professor at Winston University.