On the surface he is a smiling, happy-go-lucky youngster - a quick-witted German with an easy charm and an ability to crack jokes in several languages.
There is another Sebastian Vettel, though - a fierce competitor whose ambition is measured in thousandths of a second, the imperceptible fragments he hopes will separate him from the rest of the Formula One pack at Sunday's Abu Dhabi Grand Prix and make him the sport's youngest world champion.
It is when they do not that the second Vettel emerges. The 2009 Brazilian Grand Prix - last year, as this, the penultimate race before the season finale at Abu Dhabi - was a typical example of this.
Vettel drove a strong race, starting 17th on the grid to finish fourth, but the rival in his slipstream - Jenson Button - did just enough to clinch his first F1 world championship and extinguish Vettel's faint title hopes.
As one party celebrated post-race, the other skulked behind the pits, a stark, unsmiling contrast to the familiar public persona.
When he joined Red Bull-Renault in 2009, he immediately charmed his mechanics by speaking to them in Cockney rhyming slang, but they are all acutely aware of his inner ruthlessness.
"For me," he says, "that Brazil thing was the moment when a dream stopped - last year, at least - and such moments are bitterly frustrating for anybody ambitious.
"I wasn't angry, just extremely disappointed. You work hard, you believe in something and it can be difficult to deal with the consequences when it doesn't happen. It's only natural to show your emotions.
"Do I enjoy my job? Yes. Do I enjoy it a lot? Yes. Do I have a reason to smile? Yes. But am I here only to have fun? No. I have targets and I'm ready to sacrifice a lot to achieve them.
"Generally I think I'm a happy person, I'm not trying to be something I'm not, though - I'm no actor and have always believed an honest approach is best."
Nevertheless, it is the perkier of the two Vettels who has been the dominant partner since he got his major career break in 2007.
Promoted to motor racing's big league as reserve driver for the now-defunct BMW team, he made his F1 race debut in that season's United States GP and became the first teenager to score a world championship point, at the tender age of 19 years and 349 days.
BMW were not fully convinced of their junior's long-term potential, however, and before the campaign's end he had been released to race for Red Bull's sister team Toro Rosso, who needed a driver after dispensing with the services of Scott Speed, who had under-performed.
Eye-catching wet-weather performances in China and Japan underlined that BMW might just have been a touch hasty in discarding him and Vettel earned a full-time seat with Toro Rosso in 2008, dominating the rain-hit Italian Grand Prix from pole position to become F1's youngest winner, at the age of 21.
His subsequent promotion to Red Bull was a foregone conclusion and he has been a frequent podium visitor ever since.
His successes include, of course, an historic first: victory in the inaugural Abu Dhabi Grand Prix, the final race of the season last year. This gave him a terrific boost to head into the winter and revitalise himself for this season's championship challenge, which has seen him win four times and claim nine pole positions as he has established himself as one of the fastest drivers in the sport.
From where does he summon his competitive drive?
'I'm not sure," he says. "I tried most sports when I was younger - and I hated sharing. I didn't really enjoy football, for instance, partly because I wasn't very good - perhaps that's why the others never gave me the ball.
"Mainly, though, I think I'm selfish, as you have to be in F1: I want to do things on my own terms.
"I always want to be first, and to be better than the rest, no matter what I do, even silly stuff. If I go running at home with friends, I always want to be one step ahead. In that situation it serves no purpose, but you need that urge if you want to succeed."
Driving an F1 car, he says, "is nice, it's a lot of fun and not many people enjoy such a privilege, but the driving on its own isn't enough. The important thing is being able to win races and fight for the title".
Arguably without bad luck he could well have been already crowned champion this season. Three times this year in Bahrain, Australia and Korea, mechanical failures have denied him wins when he was ahead.
It's a common belief that contemporary Grand Prix stars have little grasp of the world beyond the high-tech cockpits that contain them once a fortnight, but - like teammate Mark Webber - Vettel has his feet on the ground and an understanding of the bigger picture.
Additionally, there probably aren't many 23-year-old Germans with an unbridled passion for 1970s British comedy - Monty Python's Flying Circus and Fawlty Towers are particular favourites - and an intimate knowledge of The Beatles.
"I'm still listening to the same music as I used to," he says, "but unfortunately The Beatles haven't released much new stuff ."
Before fame struck, he could often be found trawling second-hand record shops in his native Heidelberg region for interesting bits of vinyl - and in some parts of the world he still does. His fame has, to an extent, curtailed his hobby.
"It depends where I am," he adds. "In Germany it's no longer so easy to walk around anonymously, but it's how you deal with it that counts.
"I regard myself as a normal guy. I love my job - and lots of other people like it, too, which brings a degree of fame, but I don't walk around wanting people to look at me.
"I'm just another face in the crowd, but you have to avoid some situations because they can be uncomfortable."
By rights, he should be part of the download generation, but "I prefer to buy music from a shop, because there's a sense of touch, feel and smell - particularly with vinyl. I love taking it home and hearing the scratches as the music starts - it has so much character. I know you can get exactly the same thing at the click of a mouse, but it's not the same, is it?"
And there's something else, which brings us backs to tracks of a different kind: "Besides, looking around old record shops you might get an unexpected bargain through good fortune."
Those competitive instincts stretch far beyond the racetrack.
