York's first TV series was "Going My Way" (1962-63), based on the 1944 Bing Crosby film, but it is his co-starring role on "Bewitched" for which he remains best known. York remained with the show from its debut in 1964 to 1969, when problems stemming from an old back injury forced him to leave; he was replaced by Dick Sargent, who continued in the role until 1972.
In the years after his retirement from acting York was active with his private fund-raising effort called Acting for Life, soliciting money for the homeless by telephone while confined to his home by emphysema and a degenerative spinal condition.