Christopher Reeve was 21 in The Norming of Jack 243 when he played the character 'Max 67'.
That was over 48 years ago in 1975.
This was his first recorded movie acting credit (although may not technically be his first actual acting role).
In 2004 he died aged just 52, starring in 62 films in his career, 61 of those after The Norming of Jack 243 was first released. If he were alive today he would be 71.
In The Norming of Jack 243, I think Christopher Reeve looks: