The series centers on the fictional characters of the Russo family, which includes Alex (Selena Gomez), her older brother Justin (David Henrie) and their younger brother Max (Jake T. Austin). The three Russo siblings are wizards in training and live with their Italian-American father Jerry (David DeLuise), a former wizard, and their Mexican-American mother, Theresa (Maria Canals Barrera) who is a mortal. Alex's best friend Harper (Jennifer Stone) also found out about the Russos' wizard powers in season 2. The siblings have to keep their secret safe while living in the mortal world. When they become adults, the three siblings will have a wizard competition to decide who will become the family wizard of their generation and keep his or her wizard powers. Harper used to have a crush on Justin, but now is in love with Justin's best friend, Zeke, who finds out about the Russo's wizard powers in season 4. Alex Russo (Selena Gomez) and Justin Russo (David Henrie) are the only characters to appear in every episode of the series.
Alexandra Margarita Russo (Selena Gomez) is the only female out of the three Russo siblings, and the middle child. She is sly, rebellious, outgoing, and usually underachieves when it comes to school. She often gets into trouble because of her constant schemes (usually involving magic). She is part Latina and part Italian. Even though she is infamously known for doing the worst in wizard studies and school, and relentlessly torments her older brother Justin, Alex becomes much more mature throughout the series. Although she's somewhat lazy, Alex is smart, loyal, and caring. She goes through a long term relationship with Mason Greyback, a purebred werewolf. She becomes the Russo family wizard at the end of the series. Usually, her mom calls her "m'ija", which is Spanish for "my daughter".
Justin Vincenzo Pepé Russo (David Henrie) is Alex's and Max's brother, and the oldest of the three Russo siblings. He is very smart, and is often considered a nerd. He is in numerous clubs and has learned over 5000 spells. He continues his wizard studies in a Monster Hunting course. For his knowledge in wizardry, he takes after his father Jerry, who originally won the Wizard Family Competition against Kelbo and Megan. Unlike Alex, he is an overachiever when it comes to school. He is fairly athletic, and very respectful to his parents and other adults. Justin is responsible, sensible, kindhearted and hardworking, but can be a little sarcastic to Alex and Max. He revealed to Alex that he is jealous of her because he felt she is blessed with magic skills that he can't live up to, and it's reinforced when he refers to Alex as "daddy's little princess" (a unique, and often favoring, bond between a father and daughter). This is what drives him to be a better wizard. Alex consoles him by stating that he is her rock and foundation, and that she is actually jealous of his academic achievements, even though she openly admits to not caring about school. He has a long-term relationship with Juliet Van Heusen, a teenage vampire whose family runs the "Late Night Bite" (local competition for the Waverly Sub Station), which prompted a feud between the Russos and the Van Heusens. At first, their love is a forbidden romance, which Alex points out by referencing William Shakespeare's Romeo and Juliet, but then they eventually start dating openly. Justin reveals to Alex that Juliet is his true love, after he felt heartbroken about being unable to see her due to the feuding families. Justin gets heartbroken again when Juliet was forced to break up with him due to her getting scratched by Mason the werewolf, as she stated that when that happens a vampire's appearance will revert to their true age.
Later in the series, Alex tells the world that they are wizards and her and Justin's levels move down, so he makes a class with students who got kicked out of WizTech and later falls in love with an angel named Rosie.
At first, it seems that Justin won the Wizard Competition after being the first to cross the finish line, and he was about to be granted his full powers, when he says that he can't accept it because he didn't really win; Alex would have won if she hadn't come to back to help him, and he says that she deserves to be the Russo family wizard. Because of his honesty, Professor Crumbs allows both Justin and Alex to keep their powers and for Justin to take over as Headmaster of Wiz Tech.