Well, it's got one of the fungal leaf diseases which are common on maples, or so it seems. Could also be drought or heat damage or possibly from air pollution/chemical injury, but that's probably not too likely The good news is, while it looks bad, if its a disease, these diseases rarely, if ever, hurt the tree. Generally, these diseases are only treated with preventative sprays before and at bud-break in the spring, so not too much you can do now. I'd give the tree some extra fertilizer and try to promote a fresh flush of growth yet this year. More of a cosmetic problem than anything.

Thanks. I can easily believe something fungal with the wet spring we've experienced. Certainly no drought. Only chemical/pollution problem would be the quick whiff of car exhaust when the mail carrier stops to deliver the mail. The maple is next to the mailbox. I'll give it a good feeding of worm poop. Thanks for your help.

What kind of maple is that?

I think it's probably a sugar maple. It's a seedling I found in the garden and transplanted last summer. It seems to be recovering with some new growth.