Phlox is the chief medical officer aboard the starship Enterprise.
Phlox has three wives, each of whom has two other husbands. Only one of his wives, Feezal, was seen on the show. Phlox has five children by his wives: two daughters, both of whom, like him, work in the medical field, and three sons, one of whom, Metis, was estranged from his father for some time.
The doctor is portrayed as having an open mind to other species and cultures, even the Antarians, a race that was once at war with the Denobulans. His sickbay contains an interplanetary zoo of animals, some of them as food for other animals which are used as source for medical drugs.
Phlox is curious with a wry sense of humor, and has an affinity for Earth cuisine, particularly Chinese food (especially egg drop soup). He is also interested in religion: he once prayed with a group of monks which visited Enterprise, spent a week with monks at a Tibetan monastery, attended Mass at St. Peter's Basilica in Rome, and observed the Tal-Shanar ritual at the Vulcan compound in Sausalito.
Phlox's physical abilities have been revealed gradually over time. He appears to need little sleep, instead embarking on an annual "hibernation" of sorts that lasts for six days. Phlox also has great control over his facial muscles, being able to open his mouth wider than humans, as demonstrated by the impossibly large grin he occasionally sports. ("Broken Bow", These Are the Voyages...) When confronted with loneliness, his people can sometimes create incredibly realistic hallucinations. ("Doctor's Orders") When threatened, Phlox has the ability to inflate his head like a blowfish to scare off attackers. ("Home")
When the ISS Enterprise is destroyed by the Tholians, Phlox and other survivors transfer to the USS Defiant, which has been commandeered by Commander Jonathan Archer. Eventually, Phlox is convinced by the Mirror T'Pol and Soval to join a rebellion against the Terran Empire, and attempts to sabotage the ship, but is stopped by the Mirror Charles Tucker III.