Arwin Quentin Hochhauser (played by Brian Stepanek) is a wacky Greek-American inventor who works as a stationary engineer for the Tipton.
Arwin was a professional bowler, as illustrated in "Bowling", but quit when he lost his ball on the backswing and hit his mother in the head, shrinking her by a foot during a championship match.
Arwin is considered childlike by many characters in the show; he enjoys picture books, sleeps with a sock monkey, and eats a lunch packed by his mother.
Arwin makes a guest appearance in The Suite Life on Deck via web chat on Cody's laptop in the episode "It's All Greek To Me".
In the episode "Computer Date", Arwin boards a ship and creates a supercomputer dubbed "Cal" (until he found out it was female, renaming her "Callie") to make the SS Tipton run more efficiently.
However, it all goes downhill when Callie develops romantic feelings for Cody, causing her to go haywire and start to remove everyone else, and Arwin is forced to shut her down.
Esteban Julio Ricardo Montoya de la Rosa Ramírez (played by Adrian R'Mante) is the head bellman at the Tipton.
It is revealed during the series that his full name is "Esteban Julio Ricardo Montoya de la Rosa Ramírez".
Lance Fishman (played by Aaron Musicant) is the Tipton's handsome if somewhat slow-witted young lifeguard, who projects a relaxed and easy going demeanour, but harbours an almost unhealthy obsession with water.
He is frequently shown in scenes trying to steer even the most mundane everyday conversations to swimming, the ocean, or sea creatures in some respect.
Holding onto said women is another story: Maddie dumps him because she finds him dull, and London agrees to break up with him after he meets a woman called Wanda.
In the episode "Rock Star in the House", Wilfred is very strict about London's behaviour when it comes to celebrities, and has much concern for her education and growing as a person.
He likes coconut flavoured chewing gum, and dislikes Maddie because she does not stock it (as shown in the episode "Big Hair and Baseball").
Millicent (played by Kara Taitz) is Maddie's replacement at the hotel's candy counter while she is at camp and in Antarctica saving the penguins.
Max (played by Alyson Stoner) is one of Zack and Cody's friends, she is a girl who usually wears pigtails in Season 1 and is sometimes mistaken for a boy.
Barbara Simka Brownstein (played by Sophie Tamiko Oda) is a Japanese American, Jewish girl who dates Cody.
In the episode "Club Twin", she becomes addicted to sugar and kisses Cody, and later goes on a date with him in "Miniature Golf" and "A Tale of Two Houses".
In "First Day of High School", Mark announced that he knows Taekwondo and takes classes at the Tae Kwon Deli but chooses to be a "nerd".
Sister Dominick (played by Marianne Muellerleile) is Maddie and London's strict teacher who works at Our Lady of Perpetual Sorrow.
When she gets Maddie to attend Camp Heaven on Earth as a counsellor, it is revealed that she owns a motorcycle and searches the campers in the fashion of a prison warden.
Corrie (played by Vanessa Hudgens) is a schoolmate of Maddie, Mary-Margaret, and her idol London at Our Lady of Perpetual Sorrow.
She is seen transferring to Cheevers High School in "Bench Warmers", and is made fun of by the cheerleading captain who makes the comment of: "Now I see why she (Our Lady of Perpetual Sorrow) was so sad".
Kurt Martin (played by Robert Torti) is Zack and Cody's father, and Carey's ex-husband who first appears in "Dad's Back".
Some parts of her personality seem to be reminiscent of the Wicked Witch of the West from The Wizard of Oz; for instance, in the episode "Bowling" she states, "I'll get you next time, my pretty, and your little shtaff too!"
In "Cody Goes to Camp" Mr. Moseby was horrified at the thought that Portia might teach London how to drive as she once drove her father's yacht through piers 10, 11 and 12, because of being distracted putting on sunscreen.
Arturo Vitali is a fictitious famous fashion designer who is mentioned multiple times in the Suite Life franchise.
In The Suite Life of Zack & Cody crossover episode "That's So Suite Life of Hannah Montana", Maddie and Esteban switched the labels of one of Vitali's dresses (incorrectly spelled as A. Vitalli) and Raven Baxter's dress, to fool London into thinking she was wearing Vitali's design (but actually it was Raven's), since London was being a fashion-snob.
Arturo Vitali finally made an appearance in The Suite Life on Deck episode "Frozen" (portrayed by Todd Sherry), where he retired to the SS Tipton because he was suffering from a creative block.
Leah (played by Jaelin Palmer) – Was at "Camp Heaven On Earth" with Maddie; she was mistaken for a co-counsellor due to her height, bringing her actual age into question.
Wayne Wormser (played by Jareb Dauplaise) works as the Assistant Manager at the Paul Revere Mini-Market with Zack and Cody.