In her first appearance, in the strip from May 12, 1980, she is introduced to Snoopy by Olivier. Initially, Snoopy does not want her to join his Beagle Scouts. He changes his mind when he finds out that Harriet has made an angel food cake with seven minute frosting.
In a series of strips from October and November 1980, it is reported that the birds went to a bird bar where some blue jays started picking on them. Harriet fought back by hitting the blue jays in the face with an angel food cake. For doing so, she goes to jail (actually the humane society), and gets bailed out by Charlie Brown.