He is the somewhat uptight manager of the Tipton Hotel, who speaks with a wide vocabulary and an urbane vernacular, along with speaking a number of different languages besides English (French, Japanese, Swahili, Spanish, etc.). He is often annoyed by Zack and Cody's schemes (to the point that he may have vowed never to have any children of his own), but although he acts as though he does not care about the boys, he actually has a great deal of affection for them. For example, when they went to the baseball game and he caught a ball for Cody, ultimately making him the most "hated man in Boston". In the episode "The Ghost of 613", it is revealed that he started out at the Tipton as a bellhop back in the 1970s and had a "voluminous 'fro". In another episode, it is stated that he lives in a condo. Mr. Moseby is probably more of a father to London Tipton than her own, because he is seldom around, he even said he taught London how to walk, her ABC's, how to ride a bike, how to roller skate, and how to drive (or tried to). He cares for London and treats her like his own. He also helps London with any problems she is having. He was also known as the "Meanager". A running gag of the series is that Mr. Moseby often makes a fool of himself in front of people (eg: hitting a baby doll that wouldn't stop crying against a chair when a woman with a baby walked by or stating he was an Egyptian belly dancer named Melina (at which a guest turned around and stared at him curiously), or making a sarcastic comment about himself (that the customers think is true, and not sarcastic). He is guessed to be 39 because he said "only 26 more years til retirement" in "A Tale of Two Houses" and it is revealed that you must retire at the Tipton at age 65 in "Free Tippy".
In The Suite Life on Deck he is somewhat an uptight chaperone on the S.S. Tipton. Though the job of putting foil to Zack and Cody's antics never goes away. He's constantly running from stem to stern keeping the boys, and London, out of trouble.
In the Jessie episode "Karate Kid-tastrophe" he was reassigned as the manager of the Tipton Hotel in New York City. Emma Ross, who is experiencing an series of severe mood swings which cause her to dress in ways that irritate adults (among other problems), and has run away from home to rent a room there. The Ross' nanny Jessie Prescott encounters him while trying to talk her into coming home. Moseby suggested that Jessie simply try talking to Emma about her behavior. Later on he had a cell phone conversation with Cody Martin over how much the nanny/would-be actress looks like Bailey Pickett.
- Carey Martin - Mr. Moseby always says he's fond of Carey
- The Cheetah Girls - The Cheetah Girls appeared in "Doin' Time in Suite 2330" in which he got their autograph.
Nia (played by Giovonnie Samuels) - Nia is Mr. Moseby's 16 year old niece. She has a part time job at the candy counter, filling in for Maddie during her absence. Her purpose for staying at the Tipton for the summer is so Mr. Moseby can get her to behave like a responsible girl. One of Nia's aunt's named Aunt Lily was to make her behave like a responsible adult, but she couldn't stand Nia so much that she changed her name and moved to Alaska. Nia currently appears in six episodes in Season Three. According to Mr. Moseby, she was expelled from her last school for fighting with the cafeteria lady because she was out of motzah ball soup. In the episode First Day of High School, she is seen defending Zack from a jock. Beulah Moseby - Beulah is Mr. Moseby's mother. She favors Mr. Moseby's brother Spencer over him but she still loves him. Beulah was mentioned in the episodes Big Hair & Baseball, Moseby's Big Brother, Risk It All, and Miniature Golf. Her name Beulah was revealed in the episode, Miniature Golf. In Big Hair & Baseball, she was so mad at Mr. Moseby that she sent him a nasty message on his cellphone, and she has a woman who waxes her lip (indicated in the episode Risk It All). Beulah appears to be sort of mean and she wants Mr. Moseby to get married. She is also described by Mr. Moseby on one occasion as being 250lbs of fire and brimstone, and 20 lbs of coffee cake in Miniature Golf. Rose Moseby (Phill Lewis) - Mr. Moseby's grandmother and was in the episode, A Nugget of History. She helped Zack get an "A" in history. She carries a large purse filled with many objects that realisticly wouldn't fit into it like a baseball bat, vacuum cleaner, anchor ect. (similar to Mary Poppin's purse). Spencer Moseby - (Dana Michael Woods) Moseby's older brother, who is a midget. He is filthy rich, mean and is lactose intolerant. Spencer worked for the Tipton for a while when he was broke, but quit when all his riches came back. Spencer would make fun of Mr. Moseby's lack of accomplishments when compared to his own, and Mr. Moseby's hate for Spencer eventually built up, resulting in a very immature fight between both of them in the hotel lobby (which actually was a wrestling match). Lily Moseby - Lily Moseby is the one who was to take care of Nia before Mr. Moseby. But, as Nia mentioned, this did not go well and she changed her name and moved to Alaska. It is unknown if she is Mr. Moseby's sister or cousin.