Robert Mitchum was 29 in Out of the Past when he played the character 'Jeff 'Bailey' Markham'.
That was over 77 years ago in 1947.
In 1997 he died aged 79, starring in 139 films in his career, 104 of those after Out of the Past was first released. If he were alive today he would be 106.
In Out of the Past, I think Robert Mitchum looks: