Without kicking a ball in the Premiership, he has managed something that has eluded the rest of the Premiership.
Within six years of leaving primary school, he has been transferred for £12 million. He is the most expensive 16 year old in football history, ready to adorn the costliest stadium next season.
Arsenal, often accused of parsimony in the transfer market, have committed £22 million to securing new players in a week. The emphasis is very much on the future, and expectations are heady.
Walcott's transfer to Highbury is the culmination of a four-strong battle for English football's most coveted teenager. Rafael Benitez, noting Walcott's support for Liverpool, then opted not to join in the auction, preferring to prioritise players whose first-team career predated the Spaniard's search for a right winger.
Tottenham, having raided three other Championship clubs for wingers in a year, were unable to add a fourth. Only Manchester United made no move as Sir Alex Ferguson opted for defensive reinforcements instead.
As ever with a transfer involving Rupert Lowe, there is a touch of controversy. Walcott, at 16, is unable to sign a professional contract until March. But, had he walked out on Southampton, a tribunal would have determined the fee.
The winger's insistence that they negotiate with Arsenal guaranteed the south coast club a greater windfall for their role in his development, though the choice of Chelsea would have been more lucrative for both chairman and player.
Even in his departure, then, there was a touch of loyalty towards Southampton. Among the other praise he has generated was a compliment from Harry Redknapp. 'He's got brains,' said the former Southampton manager after Walcott was a disinterested spectator in a 19-man melee at Hull (the two goalkeepers were the only other non-participants).
And while comparisons with Wayne Rooney, the teenager to command the greatest fee and now a comparative veteran of 20, are inevitable, they are, age apart, wide of the mark. Rooney's rancorous move to Manchester United is one difference, his fiery temperament another.
Rooney craves a central role, while Walcott is equally happy on the flanks. Moreover, while the barrel-chested scouser emerged, seemingly, with the physique of a 28-year-old, Walcott is a slight figure. Brushing Rooney off the ball never appeared simple, but defenders may suspect Walcott will be an softer touch.
Indeed, he has been timed over 100 metres at 11.5 seconds. But that was two years ago, and Walcott reportedly eased up before the finishing line. The presumption has to be that he could now run at least half a second quicker.
The prospect of two Thierry Henrys, therefore, should be terrifying. And as Charlton's Dennis Rommedahl has always insisted that tales he was timed at 10.4 seconds are apocryphal, Arsenal will have a pair of contenders for the title of the Premiership's quickest player.
It is impossible to ignore Walcott's speed, but there has been much else to admire since an eye-catching debut against Wolves on the opening day of the season. The journey from fringe to star player has been a brief one. Five goals - in 20 appearances - show he is not yet a predatory forward or the most clinical of finishers, but a deft left-footed lob from an acute angle against Luton ranks among the strikes of the season outside the top flight.
Moreover, though right-footed, he is equally adept on either wing or as a central striker, offering skill to complement his acceleration. Given the value Arsene Wenger attaches to pace, technique and versatility in his attackers, and his lack of interest in one-dimensional forwards, it is easy to see why Walcott found favour with the Frenchman.
Though more prolific, he can be compared to Jermaine Pennant, another fine crosser with a propensity for jinking solo runs. Pennant, of course, is also a predecessor at Highbury, a teenage wunderkind supposedly destined for greater things. But for the English graduates of the Arsenal academy, the best case scenario recently has been a transfer to Birmingham or Reading. A reason to avoid Arsenal, perhaps, but they offer greater stability than Southampton, on their fifth manager since Walcott started his GCSE courses.
And the products of a youth policy nonpareil are fast-tracked into the first team, whereas England internationals can rot in the reserves at Chelsea.
Indeed, as Shaun Wright-Phillips retreats further into woolly hat and padded jacket on a heated Stamford Bridge bench, could Walcott - along with Pennant and Aaron Lennon - emerge as an outsider for the World Cup squad?
As such, he will be at the forefront of the Ashburton Grove generation.
Goalkeepers apart, Wenger can field a full team and bench of players aged 22 or under (Eboue, Djourou, Senderos, Clichy; Walcott, Fabregas, Diaby, Reyes; Adebayor, Van Persie, with a choice of replacements from Flamini, Lupoli, Owusu-Abeyie, Song and Gilbert). Arsenal's future, then, holds more appeal than their present
Not that realising his potential is guaranteed. The dangerous combination of youth and price make Walcott, as Arsene Wenger has admitted, his biggest gamble in the transfer market, especially for a player who is untried in top-flight football.
But as the last few months of Theo Walcott's formative career have shown, sometimes you should believe the hype.
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