It hasn't been revealed in any episodes what his real name was, but River Song knew his name.
In both The Armageddon Factor & The Happiness Patrol the Doctor's nickname at university was revealed as Theta Sigma. Other noms de plume include John Smith, the Oncoming Storm (in Dalek legends) and the Ka Faraq Gatri.
Name are something of utter importance to the Doctor and other Time Lords, and if you look at the Doctor's face after River whispered his name to him, you'll notice his face is quite shocked. And after reading the Doctor's mind, Madame de Pompadour (Reinette) says of the Doctor's name: "It's more than just a secret, isn't it?" .
We know that he chose 'Doctor' to be known as (as the Master chose 'Master'). We also can infer he's had the name for a long time. We don't know why he choose the name "Doctor".
In one of the early NAs, it is rather implied that the name came from his doctorate, the highest academic degree that he was able to achieve, and one that was considered to be rather inadequate from the point of view of his family's ambition for him
Nobody knows the Doctor's name, because none of the writers have ever invented one for him. And they likely never will. Current show-runner Steven Moffat explained that any name they give him now would be anticlimactic, and take away from the mystery of the show without adding anything new, and many of his predecessors (and equivalents in other media, like the novel range editors) said the same thing. We do know that he calls himself "the Doctor", and sometimes "Theta Sigma" (an old Academy nickname, and possibly later an undercover name), and other aliases like "John Smith", but none of those are his real name.
In-universe, of course, the Doctor knows his name, and there may be a few others.
In the past, there were many Time Lords who knew it, but they're all dead now (although of course the Master has never been good at staying dead). Plus, a few of his companions knew it, but they may all be either dead or unable to remember it. (We know he told Peri Brown, but she couldn't pronounce it and could only remember the first syllable; in the novels he told Sam Jones, but she's dead; Donna likely got the knowledge while she was Doctor-Donna, but can no longer access any of those memories without her brain burning out.)
In fact, the only people we know of that know the Doctor's name are the Doctor himself and (probably) River Song. And it seems likely they're the only two, period—one of the New Series Adventures novels confirms that before he told River, nobody alive knew his name, but even if you ignore the novels, it's hard to think of anyone else who'd be likely to have that secret.
And his name is a very big secret. There have been hints going back to the classic series (e.g., Lady Peinforte in "Silver Nemesis"), but series 6 made it as blatant as possible: the First Question, the question that can never be answered, the question that's the core of the Silence's beliefs, is "Doctor Who?"
It may be worth noting that the Doctor accidentally says his name in "Return of the Living Dad", after he has been drugged or something. Unfortunately, author Kate Orman unsportingly doesn't tell the reader what he actually says, although the character to whom he is speaking comments that it would be difficult to address an envelope with it (a reference to long Gallifreyan names such as Romanadvoratrelundar)
|This page needs a major clean up or extra information added because
You can clean up this page by hitting edit above. Once this page has been cleaned, please remove this template from the page.
- Who is the Doctor
- What did River Song whisper to the Tenth Doctor in The Library
- To whom has the Doctor told his name