My opinion's probably useless without a longer discussion... but I don't get any N vibes off her when I've seen her. Never have. (Just sayin'.)
She started off interested in the Arts (ballet, piano, singing, band geek), chose to be a Chemistry major in college and went quite far with that before she switched to theatre, then stopped working for many months to pick up the martial art known as Krav-Maga (this was before Alias ever existed), then she auditioned for TV; the interview quotes her as saying, "I really wanted to be a children's author"
if we're going by
The Liquid Laser's definition of an N type being likely to move around, she seems to qualify. "I would just like to have as varied a career as I can" also, "I definitely think if I never got another job, I'd go to grad school!"
" limbs that she doesn't seem quite in control of despite years of ballet training." She's been said to be quite klutzy (noted especially when she tripped walking on stage to present an academy award; the interviewer also comments, "Walking across the Getty courtyard, Garner loses her balance again, but manages to spare the fanny-packed tourists the sight of a famous actress face-planting.") despite her pwnage of martial arts. Suggests inferior Se, which would make her a dom Ni.
In my personal experience, Scrabble lovers are also N types; does anyone have any similar/contradictory personal experience? ("says a good date night with Affleck is if she's at the stove and there's Scrabble involved.") Affleck is also pretty universally typed as an ENFJ.
Rarely wears makeup/jewelry to any event where it's not necessary; claims to have zero fashion sense.
"It was never my goal to become famous or to walk a red carpet for that matter. It was always my goal to get the next job and then once this was in sight, it became my goal just to try to have more choices."
TeenHollywood.com - Jennifer Garner: Everything That's Fun to Know...Part I
"it wasn't important to me to be part of the cool crowd. If you could see pictures of my eighth grade birthday party, we were really, really a motley crew." (Would that be universal to SJs? Or do SJs just need to belong somewhere?) "I also took jazz but I was always a disaster at jazz. I've never had rhythm.".... if she is SP I would be extremely surprised.