Shaves his hairline?

He does it for Mad Men to look older.

I'm pretty sure that's his real hairline. It's been receding for a while now.

"I saw the best minds of my generation destroyed by madness"

You can clearly see the shave shadow of more than an inch. He's got hair there. The show has required him to shave it back to make it appear his character is aging. He looks too young for the storyline and needs to appear older. George Clooney did the same thing for 'Out of Sight' in '98. You could also clearly see the shadow of his actual hairline on the blu-ray because of the extreme clarity and quality of the transfer.

It's all explained here as to why they shaved it back and asked him to gain 25 pounds...
http://www.vulture.com/2012/06/mad-mens-vincent-kartheiser-on-petes-ha irline.html

Wow, I don't watch Mad Men but just saw some pictures of him on the IMDB front page and was taken aback by his aged, bloated look.

I could not believe he had changed so much.

That link you provided explains it, then.

He must be really commited to the role to alter his physicality in such a way.

Hope he doesn't permanently damage his body with the extra 25 pounds.

I hope his health doesn't suffer too badly, but they are paying him well I'm sure and that show's been on a long time. He'll be alright.

Well you can put on a healthy 25 pounds. He's also not exactly overweight.

Ah, my bad.

"I saw the best minds of my generation destroyed by madness"

no big whoop