Frederick was born during Cheers's eighth season episode "The Stork Brings a Crane". He was delivered in a taxicab while Lilith was on her way home from the hospital after an episode of false labor. Lilith tolerated the pain by biting down on one of the cab driver's fuzzy dice. Initially his personality is very undeveloped, as he is just a small child. In early seasons he is portrayed as having numerous rather debilitating allergies and being rather inexpert when faced with a number of more or less mundane social situations (as seen in the fourth season episode A Lilith Thanksgiving). He is known to be intelligent, achieving high academic scores, and is accepted to the Marbury Academy, an exclusive Boston private school. In addition to his intelligence he shares several family traits, including a talent for chess, and his mother's talent at Machiavellian scheming based on an understanding of behaviorist psychology. He shares both his Uncle Niles' lack of coordination and his spelling skill, becoming one of the two final contestants on the National Spelling Championship. As he gets older more traits begin to develop. At around seven he develops a crush on Daphne, much to Niles' jealousy. As he gets older he begins to get somewhat spoiled and surly, and enjoys Frasier's company less and less, prompting Frasier to fear a growing generation gap, particularly when Freddy becomes a goth, but father and son are able to bond over their mutual bad luck with the opposite gender. At the end of the series he is 15 years old.
Frederick's chronologically last appearance in the Cheers/Frasier universe is during the epilogue of the tenth-season Cheers episode "I'm Okay, You're Defective", described as taking place "Many years later". It shows an older Lilith and adult Frederick (played by Rob Neukirch) sitting for the reading of Frasier's will.