Wilson is Tim Taylor's neighbor and confidant. He frequently gives advice to all members of the Taylor household, often reciting words of wisdom, famous quotes, or historical examples for Tim. As a running gag, Tim frequently butchered these phrases upon trying to repeat them (with the effect of making the advice unintelligible/non-sense).
Wilson was born in Chicago. He has traveled the globe, learning much from virtually every culture in existence, and his house contains a veritable treasure trove of artifacts, along with a pet parrot named Mozart who appeared infrequently. Wilson was married at one point, but his wife Catherine died before the series began. Wilson somewhat represented a "God figure" in the show, always doling out advice to the Taylor family, and seemingly knowing just what to say to solve a problem.
He earned his Ph.D in Forgotten Languages and Cultures.
The character Wilson was partly inspired by a neighbor that Tim Allen had when he was very little; he was too short to see over his neighbor's fence, and therefore unable to see his neighbor. Thus, Wilson is a type of unseen character; the lower half of his face is always obscured by some kind of object, usually the fence. On the rare occasions he's seen outside his yard, he's still blocked by something (a scarf, a plant, etc), yet no one seems to notice. Sometimes the top half of Wilson's face is obscured while the lower half is revealed, and on at least two occasions his entire face was visible, although hidden behind Halloween or clown makeup. In "The Karate Kid Returns" (Season 6, Episode 14), Wilson is standing behind one of the Beach Boys, who moves forward prematurely at the end of his line, thus exposing Wilson's entire face for about a second before an abrupt camera cut. Wilson's entire face was finally revealed when the cast took their bows at the end of the series finale.