Beginning a prolific career at the age of ten, Shea is perhaps best known for portraying the title role in the NBC children's television series, The New Adventures of Huckleberry Finn, as well as for his feature film roles: as Nick in the Ivan Tors family film, Namu, the Killer Whale; as Jimmy in the MGM western, Welcome to Hard Times; and as "Cav" in the Walt Disney drama, Ride a Northbound Horse.

[1] After Shea was released from his obligations for Joshua, the family remained in California where he was soon landing guest-starring roles on such popular television shows of the time as Blue Light, Camp Runamuck, and The Fugitive.

[1][2][4] In 1967, Shea landed a co-starring role in the western film Welcome to Hard Times as Jimmy, an orphan boy who is taken in by Will Blue (Henry Fonda) after his father is murdered by a vicious stranger terrorizing their small town.

[1][2][8][9] Reportedly beating out over 1,300 other boys for the role, Shea starred as the titular "Huck Finn" alongside LuAnn Haslam as Becky Thatcher and Kevin Schultz as Tom Sawyer, navigating weekly adventures within an animated world as they attempted to outrun a vengeful "Injun Joe", played by Ted Cassidy.

[1] In a departure from the network's usual Saturday morning cartoon schedule, the series aired Sunday nights and made its three young stars popular teen idols of the era.

[10][11][13] The series aired in over 15 countries and its three young leads were routinely in demand to make celebrity appearances to meet with fans across the United States during the show's original run.

[1][2] Premiering on March 16, 1969, the special presentation starred Shea as "Cav Rand", a 15-year-old orphan in the old west who buys a prize race horse, only to have it stolen by a con-artist played by Carroll O'Connor.

[3][11] Shea graduated from Van Nuys High School in 1971 and, after leaving show business in 1973, began working in a patio furniture shop in Studio City, Los Angeles.