But now, the 20-year-old is going mainstream as the new face of CoverGirl, touting the brand's NatureLuxe lines of foundation and gloss balm, which will debut this winter in drugstores.
The ads will show the Pennsylvania native twirling about barefoot in a gauzy sundress with her signature blond waves blowing in the wind -- a fitting picture for products that use sheer pigment and ingredients like shea butter and cucumber water for a more natural look and feel.
StyleList caught up with the exuberant singer at New York's Peninsula Hotel, where Swift was still high on the excitement of her CoverGirl campaign.
"I remember when I was a little kid and I was flipping through Seventeen magazine or something, and I saw Faith Hill as a CoverGirl. I thought that was the coolest thing in the world," remembered Swift.
"The models are based on true individuality -- people like Drew Barrymore, Ellen, Rihanna -- people that I really respect. I thought it would be really cool to be part of a family that thought individuality is beautiful," added Swift.
"With change, there's a fine line. There's change that I'm comfortable with, there's change that my fans are comfortable with, and I don't want to go into a territory where they feel like they don't know me anymore," said Swift.
And those bangs?
"It was magic," laughed Swift.
For red-carpet looks, Swift can draw inspiration from anything from the style and feel of her dress to a passing phase she's in -- "recently, it has been Old Hollywood" -- to other stars she admires, like actress Charlize Theron.
"Charlize Theron is just gorgeous, and I heard that she does her own makeup for some awards shows. I thought that was so down-to-earth and cool," commented Swift.
As for her own beauty routine, Swifts says she religiously moisturizes both morning and night, though that's the only part she's strict about. "I'm pretty lazy when it comes to a regimen. Sometimes, I take my makeup off at night; sometimes, I don't."
(Unfair as it may seem, the singer's peaches 'n' cream complexion looks near flawless up close, in spite of the fact that she sometimes skips out on skin maintenance.)
Yet, Swift won't be caught without her beloved eyeliner -- an obsession that caused the singer, while stuck on a flight, to resort to measures so extreme that she still laughs about it today.
"When I was on a plane to Japan like two years ago...and I had no makeup with me, I went to the bathroom and used a Sharpie! I do not recommend drawing eyeliner on with a Sharpie."
To master the cat eye, Swift pretends there's an imaginary line extending upward from her bottom lash line, so that she nails just the right angle every time.
Red lips are tissued over and set with powder for a sumptuous velvet look, and Swift uses soft-sheen eye shadow in place of highlighter to bring her skin a glow.
Yet, Swift says she wasn't always so adept with a makeup brush, and went through some beauty growing pains during her school years, through which her mother tried to gently guide her.
"I was just terrible at it, and I'd come downstairs with black eye shadow all over my eyelid, and she'd be like, 'Honey, you might want to clean that up.' She was never like, 'Turn around, take it off!' She has always been really, really cool about -- we'll call it artistic expression," said Swift with a smile.
It's from that experience that Swift draws the biggest beauty lesson she wants to share with her fans.
"It's not about being like everybody else. I was confused about that for awhile when I was in school," said Swift.
"I think that whether you realize it while you're in school, or whether you realize it when you're out there in the world, figuring out what makes you comfortable... you come to realize what you like to look like. And you stop weighing it against what you think everyone else wants you to look like."
Something tells us, that somewhere, Lady Gaga is very proud.
Love Taylor's style? Click here for a roundup of her best looks.