Cast of Step by Step

Patrick Duffy plays the role of Frank Lambert, a divorced contractor and the father of three children. He enters into a blended family when he marries Carol Foster.

Suzanne Somers portrays Carol Foster Lambert, a single mother of three children. She marries Frank Lambert, forming a blended family.

Brandon Call portrays John Thomas 'J.T.' Lambert, Frank Lambert's oldest son from his previous marriage. J.T. is depicted as a carefree and somewhat rebellious teenager.

Staci Keanan plays the role of Dana Foster, Carol Foster's oldest daughter. Dana is portrayed as an intelligent and responsible teenager.

Christine Lakin portrays Alicia 'Al' Lambert, Frank Lambert's middle child and only daughter. Al is depicted as a tomboy who enjoys sports and has a rebellious streak.

Angela Watson plays the role of Karen Foster, Carol Foster's middle child and Dana's younger sister. Karen is depicted as a popular and outgoing teenager.

Christopher Castile portrays Mark Foster, Carol Foster's youngest son. Mark is depicted as a nerdy and intelligent child with a love for science.

Josh Byrne plays the role of Brendan Lambert, Frank Lambert's youngest son. Brendan is depicted as an energetic and mischievous child.