He isn't very bright, or even very literate. His newscasts are always full of mistakes on his part, which makes him the butt of jokes from almost everyone who knows him. His dressing room is a sight to see. It's a shrine to himself, with one wall full of pictures of celebrities he's pasted himself into and autographed. (We know he autographed them because they're often spelled wrong.)
Ted's inflated ego is really just all talk, though. He's really insecure about women, although he eventually finds a wife, naive Georgette Franklin-Baxter. His major fear is that he will one day be replaced by--gasp!--a competent newscaster.