As a busy juvenile actor, Doug McKeon was featured on the TV serial The Edge of Night, and was co-starred with Brian Dennehy in the 1979 prime-time series Big Shamus, Little Shamus. McKeon was 12 years old when he was honored with a Golden Globe nomination for his work in the TV production Uncle Joe Shannon. His best-known screen assignment was as Henry Fonda's surly step-grandson in the 1981 crowd-pleaser On Golden Pond. McKeon went on to make his last teenage appearance in the 1985 comedy Mischief; that same year, he made his first grown-up appearance as the title character in the TV biopic Heart of a Champion: The Ray Mancini Story. In 1975, Doug McKeon made his Broadway debut in the musical Truckload. In 1983, he stepped in for a vacationing Matthew Broderick in the starring role in Neil Simon's Brighton Beach Memoirs.