 In 1991, Giella succeeded Bill Ziegler as artist on the "Mary Worth" daily and Sunday newspaper strip.Giella retired from "Mary Worth" in 2016, with his last strip appearing on July 23, 2016.Outside comics, Giella did commercial art for advertising agencies such as McCann Erickson and Saatchi & Saatchi, and publishers such as Doubleday and Simon & Schuster.