Health-care bureaucrat who was brought in by the Dinaali to be the chief administrator of Hospital Ship 4-2 which hovered over their world. Chellick's people were known throughout the sector for their administrative skills, and before they came, the Dinaali were a dying race, plagued with eco-disasters and famine. The Dinaali contracted Chellick and others of his race to run the hospital ships and do whatever it took to make the system work, making the hard choices they didn't want to make, including letting the "Allocator" computer assess each patient and assign a "Treatment Coefficient" in order to prioritize their limited resources.
However, this meant that many patients who needed certain treatments to live were denied those treatments, because their status in society was not high enough. This system of health care was considered abhorrent by the EMH from the U.S.S. Voyager, who was sold to Chellick by a thieving Dralian trader named Gar.
Voyager's Doctor turned the tables on Chellick by injecting him with a virus that had killed a low-priority patient, and altering Chellick's blood to cause the Allocator to identify him as that deceased patient. The only cure was cytoglobin, but the Allocator denied that treatment. With his own employees betraying him, Chellick had no choice but to allow all the "Level Red" patients — which now included himself — to be transferred to "Level Blue" so they could get allocated life-saving treatments.