Trivia: All of Rich and Dana's kids (in Dana's vision of their future) are named after their parents, save for one who Rich calls Ross.
Trivia: Angela Watson, who plays "pretty but dumb" Karen won the role in a beauty pageant.
Trivia: Brandon Call's mom did not allow the hair and makeup department to style his hair for each episode. She insisted on doing it herself.
Trivia: Although the production paid to have Magic Mountain closed off for the cast and extras to film the show's opening titles sequence, the cast was not allowed to ride any of the rides for insurance reasons. The close-up shots of the cast on the roller coaster were done in front of a green screen, while the long shots were of stunt doubles.
Trivia: Sasha Mitchell was dismissed from the show after the fifth season due to allegations of spousal abuse. It was later revealed that Mitchell's wife at the time would abuse their children in drug-induced rages and that Mitchell would intervene to protect them. Mitchell would later be brought back in a guest appearance in the show's penultimate episode.
Trivia: Staci Keanan and Christine Lakin are the only cast members among the child actors to maintain an acting career after this show ended. Keanan eventually retired from acting and became the Deputy District Attorney for Los Angeles County. One of her notable cases was the trial of Danny Masterson.
Trivia: Even though her mom recorded every episode when they aired, Staci Keanan never watched any episodes of this show until 2022, 25 years after it ended. She finally started watching them ahead of launching a podcast called "Keanan and Lakin Give You Déjà Vu" in February 2024 with fellow cast member Christine Lakin.
Trivia: After completing a day of filming on September 3 1996, Brandon Call, who played JT, was shot in both arms in a traffic altercation. Christine Lakin said on the Pod Meets World podcast that she believes the incident made Call decide he no longer wanted to be in the spotlight. He retired from acting following the conclusion of Step by Step, which lends some credence to her theory.
Answer: From what I've read, the kid in question was the original actor cast to play Mark and was intended be closer in age to Brendan. For whatever reason, they recast the role with Christopher Castile and didn't bother removing the original actor from the beginning of the opening credits. I guess they figured people would just assume the kid was one of Brendan's friends.
Phaneron ★