He has to be in his 30's to 40's but I can't find anything that gives me a definite age.
Okay Well, You havent specified in what, but presuming you mean in the comics, and baring in mind he was the psychologist when Thomas Elliot and Bruce were only 7-8, then the bare minimum he could have been then was 21, though he was likely older. THEN presuming Bruce is around 35, though he also is probably older, then the bare minimum Crane could be is 48. that being said, he is likely between 48-60. He just looks good for his age ;). this of course is in the comics, however. The movie is different.
