In her earlier life, Gertrud worked as a cook for Elijah Van Dahl's parents where they had a secret love. Elijah's parents forbade this relationship between their son and one of their servants. Despite Elijah standing up to his parents, Gertrud was already gone. Some time after this, Gertrud gave birth to Oswald Cobblepot and claimed that his father was dead.
Life with Oswald
Renee Montoya and Crispus Allen visit Gertrud to report the supposed death of her son to her, although Gertrud believed a woman had taken advantage of Oswald and he has run off with her.
Oswald eventually returns home. When Gertrud gives him a bath, Oswald tells his mother that he has found a "friend" and that he is a policeman.
Gertrud is presented with a broach from Oswald, and she inadvertently gives him advice on how to take down Fish Mooney.
Gertrud is taken to Oswald's new club and looks at it in amazement. She picks up Liza's scarf, and later meets Jim Gordon. Afterward, she dances with Gabe, who later takes her home.
Gertrud sings at her son's new bar Oswald's although the audience isn't too impressed, but clap regardless. However, one heckler insults Gertrud, leading Oswald to dispose of him.
Whilst at the club Gertrud gets chatted to by mob boss Salvatore Maroni, who has a grudge against Oswald after he had betrayed him. Maroni reveals some home truths to Gertrud that her son is a cold-blooded psychopath, causing her to breakdown, and angering Oswald, who swears to Maroni he will pay. Later back at her apartment, Gertrud asks Oswald not to make a fool of her, and if what Maroni said was true. Oswald continued to deny it, but Gertrud sees right through his lies and leaves the room.
With the help of Butch Gilzean, Oswald finds her inside her cage at a warehouse and attempts to bust her out with bolt cutters. However, Theo and Tabitha Galavan are waiting for them and the gate is only accessible with a certain key. In the end, Gertrud is let out before Tabitha throws a knife in her back. Before succumbing to her wounds, Gertrud states that she is now aware of her son's activities, but still considers him a good boy. As revenge, Cobblepot slashes Theo's throat before escaping through a window.
The most defining trait of Gertrud's personality is her deep love for her son, Oswald Cobblepot, who loves her in return. Gertrud seems to see only bygone splendour and perfection around her, hardly ever harsh reality.