The Fairy Godmother transformed Harold into a human in order to marry Lillian, in return for the hand of their future daughter. When they saw Fiona become an ogress (possibly due to the Fairy Godmother), they sought her help. Lillian however, unlike Harold, didn't like the Fiary Godmother, mentionning that she didn't trust her when she and Harold went to sign their kingdom away.
In Shrek 2
She is first seen when Harold asks himself "How could this get any worse?" telling him that they need to talk. She tells him that Charming went to the tallest tower of the keep, only to find a "gender-confused" wolf telling him Fiona is already married, to which Harold responds that Charming "didn't get there in time". The trio then pass at Friar's Fat Boy, and The Fairy Godmother tells Harold that Fiona marrying Charming over Shrek is not only the best for her, but also for the whole kingdom.
When Shrek consults the Fairy Godmother to try to mend his relationship with Fiona, she dismisses them, saying that ogres don't live happily ever after. After briefly insulting Shrek (until somebody arrives), Shrek says he's leaving, but steals a "Happily Ever After" potion that he believes will restore Fiona's love for him.
The next morning, Shrek is a human and Donkey is a stallion. However, The Fairy Godmother learns of the potion's theft and manipulates Shrek into thinking that he has lost his true love for good, and Shrek, heartbroken, decides to let Fiona go, believing she will be happier than Charming.
To ensure that Fiona falls in love with Charming (and forgets about Shrek), the Fairy Godmother gives Harold a love potion to put in her tea, but Harold refuses to make her fall in love this way. The trio overhear the exchange, and The Fairy Godmother notices them and have them arrested to stop them from foiling her plans, but they are freed by their fairy tale friends. The Muffin Man makes a gigantic gingerbread man, who breaks through the castle, and Puss uses his wide eyes to distract the guards. As Charming is about to kiss Fiona, Shrek interrupts him.
The Fairy Godmother tells Charming to kiss Fiona, to Shrek's grief, but Fiona doesn't fall in love with him and knocks him out with a headbutt. Harold then reveals he swapped the cups, having realised her love for Shrek, whereaupon the fairy tale creatures stop her from getting her wand. When she reaches her wand, Shrek knocks it out of her hand, but Charming catches it, and sends it to her mother. The Fairy Godmother then reminds Shrek that "ogres don't live happily ever after" and blasts a spell at him, presumably to kill him, but Harold sends it back on her, reducing her to bubbles.
- Another Fairy Godmother appeared in the ending of Shrek, transforming four mices into stallions.
- It is possible that she is actually the witch who cursed Fiona as part of her plan. However, (if this was the case) it would have gone horribly wrong, since Shrek saved Fiona and not Charming.
- The Fairy Godmother is the first DreamWorks to use the term "bloody".