Benjamin Cohen was the father of Percival Dalton. He and his wife Edna lived in New York. Despite his fragile health (having survived a heart attack), he was a forceful and vehement personality. His determination that his grandson be raised in the Jewish faith to preserve the Cohen name put him at odds with Harriet Oleson, who was equally determined that her grandchild be Christian.
Benjamin was highly disappointed that his son Percival (born Isaac Cohen) chose to move from New York City and change his name in order to hide his faith, which Percival did believing that no one would hire him if it were known he was Jewish. Benjamin insisted on being addressed as "Benjamin," and objected to nicknames such as "Ben" or "Benny" used on himself or his grandson and namesake.
Although he had a roaring temper and a tendency to yell when upset, Benjamin could also be quite charming. He would delightedly explain the Jewish customs and traditions to Willie Oleson, for instance, and he once flattered his nemesis Harriet to speechlessness, much to the amazement of her husband Nels.
Although never seen again in the series, Benjamin had taken ill by the end of season seven, prompting Percival and Nellie to return to New York to manage his store. With his death, he passed away of illness in his sleep, their move became permanent.