To me, it looks like him in a couple of scenes -- you sort of have to see him in action too, moving his face and walking with that Inspector Luger swagger.

Here's a James Gregory head-shot of similar or earlier vintage, for comparison to the "Mad World" screenshot:



But, there's another scene closer to the end, with a cop in a grey hat, and if it's the same actor as the grey-hat cop seen earlier, well then this last time I do NOT think he looks like James Gregory.

Eric raises a good point about James Gregory gaining some recognition in "Manchurian Candidate" that same year. Of course a lot of big names did "Mad Mad World" without credit, including Jerry Lewis (who had no lines either), Jack Benny, and others -- but, those were more "featured" cameos than this cop, who is little more than an extra.

I'm curious who David had in mind, and I'm sure he'll tell us.

While I had the DVD out, I ended up checking for other candidates by watching the whole DVD at 32x speed. All I got out if that was a case f the whim-whams.

But, in the huge crowd scene in the town square near the end, standing in row 722 from the front, number 1,035 from the left, the fellow in the white hat....I think it might be Mike Lally.

Yup....definitely Mike Lally!

I appreciate the strong interest in this topic.

The suggestion of James Gregory is interesting. If he really appeared in "It's a Mad Mad Mad Mad World," I overlooked it. He was not the actor I had in mind.

According to the Internet Movie Database, Buddy Hackett, one of the main stars of "It's a Mad Mad Mad Mad World," appeared in "Walking My Baby Back Home." After reviewing the short clips of the Grace Wheeler film from "Forgotten Lady," I am fairly sure that Buddy Hackett appeared in it for only second or two. Hopefully someone out there can verify this. It would be a lot clearer to me if I had seen "Walking My Baby Back Home" in entiretly. Unfortunately I never have.

Very clever David...Very very clever!
I looked at Forgotten Lady and there is a guy there that could definitely be Buddy Hackett. It is the last scene where Grace stands up in front of the screen while the movie is running behind her. If you look really close you see a glimpse of him playing an upright piano. Then Grace's shadow blocks him. It's quick, but it could definitely be him.