It often does, which is weird as is not dealing with children etc. Though it does usually say on the application form whether or not this is required.
However at Uni my friend damaged a car in a drunken rage, got caught immediately, admitted it, apologised and paid for the damage and got a criminal record (his Dad had just died and other stuff was bad, though that's not an excuse).
So this was spent in 5 years, during which time he was doing degrees so it didn't affect anything. He then applied to Investment Banks and Hedge Funds. He didn't initially disclose it, as he is not required to, but after getting further into the interview process he did tell them as he knew they would find out and he wanted to explain etc. He still got a job.
However, we were discussing this with a friend who works at a German investment bank and he said that they wouldn't have employed him. I'm not sure on the legalities of that, but he said it was company policy, so I assume that means it has to be fully outlined to you when you are applying.
By law it is spent and if it doesn't impact on his work (i.e. the nature of the crime doesn't) then he should be ok. He doesn't have to disclose it. However if it's found out in an enhanced check, he can say that he was young and stupid and has learned a valuable lesson etc. Hopefully after a few interviews he can gauge what is best for him.
Hope that helps