Spencer makes his only appearance in the episode "Moseby's Big Brother", when he's staying at the Tipton Hotel in order to go through a big, important business deal. While Mr. Moseby is acting very tense and uptight preparing for his arrival, he tells Maddie, London, and Esteban about him, saying that he didn't always have a good relationship with his brother, because he always seemed to be upstaged by him when they grew up together as kids and young adolescents. He tells them that because he always felt like his brother cast a condescending, "giant shadow" over him, so to speak, he wants to impress his brother and make it seem like he could live up to his brother's name and reputation, even if not exactly equally. Mr. Moseby describes him as "someone he had never been able to measure up to...a straight 'A' student, got all the pretty girls, and even became a multi-millionaire by 30."
When Spencer arrives at the hotel, everyone is surprised that he is a dwarf, because of the language Mr. Moseby uses to describe him as having such a "big" image, reputation, and ego for himself. When he arrives, he acts very kindly and nicely towards the Tipton employees and London Tipton, but subtly shows his contempt for Mr. Moseby by acting very condescending and patronizing towards him. Once he goes bankrupt and loses most of his money later in the episode, he ends up convincing Mr. Moseby to give him a job at the Tipton Hotel to help him make some money and allow him to stay at the Tipton temporarily. Although Mr. Moseby reluctantly agrees and hires him, he starts taking advantage of Mr. Moseby's kindness by using his expert professional skills on the job to get away with bending the hotel rules to do whatever he wants. He also tries to use his sibling relationship with Mr. Moseby to guilt him into not confronting him about his work ethic.
After Mr. Moseby finally gets tired of Spencer's behavior and actions on the job (upon Carey, Zack and Cody's mom, convincing him to stand up to him), he angrily reprimands him for all of the times Spencer ever treated him condescendingly, took advantage of him, and tried to exploit their family relationship against him in order to get away with being manipulative, and being a jerk. Spencer agrees with him, admits his fault, and apologizes to Mr. Moseby, asking for his forgiveness. Mr. Moseby does compassionately forgive him at first, and they express their love for each other, until Spencer lets Moseby know that he was able to get all his money back when his business associate gives him back all his funding. Once he does so, he apologizes to Mr. Moseby for a prank he played on him when they were little children, shaving the word "dorky" in his hair. Mr. Moseby upon finding out that he had lied about the prank from when they were kids and remembering how he got bullied for it, gets angry at Spencer once again and they then get into a heated argument with each other about the prank. The argument then progresses into talking about each of their individual relationships with their mother, and fighting over which one she liked best. Subsequently, the conflict then escalates into a full-fledged physical, but very comical fist fight. Once they finally get tired of fighting each other after an extended period of time, they apologize to each other one last time and agree to "call it even" before Spencer has to leave again, even though they don't act too happy or content about forgiving each other.
Although he generally tries to be nice and cordial to most other people, Spencer tends to be very manipulative and often unscrupulous towards Mr. Moseby as his brother, characterized by the way he treats him through taking advantage of and exploiting him because of their sibling rivalry. However, he does show some capacity to be genuinely remorseful for the ways he used to treat his brother, and does sincerely ask for his forgiveness at the end of the episode. He is also very kind and nice, at least professionally, to most other people because of his career and reputation as a wealthy businessman. Mr. Moseby also describes him as having been a very intelligent, urbane, suave, and courteous young man, and a Casanova-like ladies' man when they grew up together in their formative years.
- He is a dwarf who is played by real life dwarf actor, Dana Michael Woods.
- He and his brother are the grandsons of Rose Moseby, however he does not mention her in the episode. Likewise, she does not mention him in her episode, "A Nugget of History," either.
- Mr. Moseby mentions him a few times in future episodes, but he is never seen again after "Moseby's Big Brother."
- His sibling relationship/rivalry with Mr. Moseby serves as a parallel to Zack and Cody's relationship in the episode.
- Mr. Moseby says when they were younger, he was a straight "A" student, got all the pretty girls, and even became a multi-millionaire by the time he was 30.