Maybe it’s just me, but the tattooed-on/heavily landscaped eyebrows on these two strike me as being in conflict with the “unsophisticated, non-european” rule.
Katie Holmes.
Did you check the eyebrows on the example you gave us? 
I did a Google image search… First page: Carrie Underwood
Michelle Obama
Alexis Bledel.
She has been likened to Audrey Hepburn, a sort-of All-American-Girl from her own day, and you can see why in this picture.
Laura Prepon before she dyed her hair…still tragic.
Maybe in that picture of her in the Coca Cola t shirt, but not in any of the others.
Agreed, she looks all slutty now, but she fit the description perfectly in the early days of That 70’s Show
Miley Cyrus seems to be the quintessential American Girl right now, as annoying as that may be to admit.
True, though there’s not much choice about painted on eyebrows in that one. 
An 18-year old Jan Smithers on the cover of Newsweek.
It’s certainly not an obsolete or outdated concept where casting directors are concerned. When they call for an “All-American” type, they want someone who is more likely to be described as pretty or cute than stunning or glamorous. Natural, but well-put together, wholesome but not prudish. She’s the girl-next-door type, but not like anyone you’ve actually lived next door to. It has nothing to do with hair color or eye color and it is not a codeword for “caucasian,” as the term frequently appears along with “any ethnicity.” (If they’re looking for a white girl, they’ll come right out and say so.)
To me the “All American Girl” is like the models you see in some J-Crew and Ralph Lauren ads. They are thin, tanned, a little athletic looking but without being jockish, not really overtly sexual, not really big breasted, a little preppy, play soccer or tennis, look smart but not bookish. They have a neat clean freshly scrubbed look. This is similar to a girl next door except the GNS is a bit more more cute, more friendly, a little less wordly, and is somehow more approacheable.
The TV show Friday Night Lights is full of them: Minka Kelly, Aimee Teegarden, and Adrianne Palicki seem to fit the bill.
I think I just threw up a little in my mouth. My kid loves this show, but Miley is seriously annoying; she gives new meaning to excessive mugging. Get that girl a new acting coach.
An All American Girl is not a middle aged Ivy League Lawyer.
For those How I Met Your Mother fans I would say Ashley Williams who played Victoria in the first season. Her sister Kimberly Williams-Paisley (Father of the Bride) also fits.
Well, to be fair, is the Ivy League Lawyer part all that relevant? If we’re just going by looks. She looks pretty all American to me.
I think there is an attitude component too. There has to be a bit of innocence, wholesomeness and unworldiness. Of course well known actors don’t have that either but they can act like they do. I don’t know what neighborhood you live in but in mine the girl next door did not go to Princeton and Harvard.
Do you really think anyone not trying to be ironic or clever would say “Michelle Obama?”
The pop-culture construct of the “All-American Girl” is devoid of irony or any kind of social commentary.
Well girls who go to Ivy League schools have to live next door to someone, right? Anyway, in my school/neighborhood lots of people went to Ivy League schools or schools just as prestigious/expensive.