Mark Foster (Christopher Castile) dancing in his boxer shorts from Step By Step (Roadie episode)

Mark dancing in his boxer shorts in the Roadie episode.

Years from now, I'll look back on this day and know I was a somebody!
~ Mark to his dad (from the episode The Un-Natural)

Mark Foster is a hero from the 1991 television series Step By Step. He looks out and stands up to threats to his blended family. Mark is a Caucasian male with blond curly hair. His signature accessory is his round glasses. His usual outfit is a conservative dress shirt overlaid with a sweater vest. He begins the show as a meek & nerdy ten year old boy. At the end of the show, Mark has grown into an assertive & well-rounded seventeen year old. He is the youngest member of the Foster side of the family. He is portrayed by Christopher Castile.

During the show's run, Mark deals with typical teen problems in addition to helping his family members. These include trying to fit in social situations, dealing with pressure to do well academically, and learning how to balance his school life with his family life. Occasionally, Mark proves himself to be human by succumbing to an earthly vice or temptation. However, his family members are always there to help him out of it. Mark's main character development is the shedding of his nerdy persona and transforming into a regular American teenager. This transformation slowly happens during the course of the series.

Mark's heroic deeds throughout the show include the following actions:

  • Hitting the winning home run for his baseball team's championship game (The Un-Natural episode)
  • Giving his brother JT solicited advice on how to be a gentleman to his girlfriend (No Way To Treat A Lady episode)
  • Sparring honorably against an opponent named Tommy and his contemptible coach in a karate match (Karate Kid episode)
  • Defending the honor of the prettiest girl in school by standing up to her ex-date's bullying during a school dance (The Wall episode)
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