Text quoted from The New Discworld Companion.

Vimes, His Grace Commander Sir Samuel. Duke of Ankh and head of the Ankh-Morpork City Watch. Badge No.177. An upright and honest man whose appointment as head of the despised Nigh Watch - regarded by all sensible people as a completely useless appendage to the running of the city - may have been the cause of his drinking problem. But it has also been suggested that he is in fact naturally more sober than other people (to put it technically, he is slightly knurd).
     It is known that he was born in Cockbill Street in the Shades, that his father was Thomas Vimes and his grandfather was Gwillaim Vimes. Membership of the Watch was a family tradition and Samuel claims to have joined the Watch shortly after leaving school. However, since he was actually in his late teens when he became a watchman this means he was either a very slow learner or is delicately avoiding the subject of juvenile street gangs, where he is believed to have picked up some of his fighting techniques.
     Initially, Vimes never got the hang of ambition and worked his way sideways rather than up; his promotion to Captain was simply the result of the sheer unthinkability of promoting any other watchman.
     By his own account he was a skinny, balding unshaven collection of bad habits marinated in alcohol, although these days he is better shaved and doesn't drink. Partly as a result of this latter fact, he is morose, cynical and ridiculously - and to his own embarrassment - soft-hearted in certain circumstances. He is almost certainly one of Nature's policemen; it has been said of him that his soul burns to arrest the Creator of the universe for getting it wrong.
     He loathes kings and aristocrats in general, despite the fact that he is, now, one of them. In fact in his earlier life Vimes was almost defined by what he disliked, and that included the undead, assassins, trolls, dwarfs and the human race. These days, with undead, dwarfs and trolls all working well in the Watch, he seems to have mellowed considerably and may even have come to terms with the human race. He still draws the line at vampires, however.
     Recent years have seen the universe play a huge joke on Vimes. He was promoted to Commander, knighted against his will and made a Duke by Lord Vetinari; in most cases his acceleration up the ranks of privilege has been part of a package to improve the standing of the Watch as a whole, but he still resents it. He also married Lady Sybil Ramkin, who is part of no package at all, and is now so rich he doesn't know how rich he is.
     For several years, he had a price on his head with the Assassins' Guild (getting as high as $600,000) but this has now been put into abeyance. It is suspected that this is because, like Vetinari, he is considered more useful too the city alive than he would be dead (the Assassins' Guild don't mind rocking the boat but draw the line at drilling holes in the hull, as it were).
     He was once blackboard monitor at school for a whole term. This fact seems to really impress dwarfs.