Scott Glenn was born January 26, 1939, in Pittsburgh, Pennsylvania, to Hope Elizabeth and Theodore Glenn, a salesman. As he grew up in Appalachia, his health was poor; he was bedridden for a year and doctors predicted he would limp for the rest of his life. During long periods of illness, Glenn was reading a lot and "dreaming of becoming Lord Byron". He challenged his illness by intense training programs and eventually got rid of his limp.