An example of a modern day tragic hero is Sirius Black from the "Harry Potter" series. Another example is Anakin Skywalker from the "Star Wars" prequels.
Tragic heroes are a literary concept most often seen in theater. It is a concept that doesn't work well with television because watching the same character make the same mistakes every week would get boring. The main principle of a tragic hero is that the character has a fatal flaw which dooms him or her to fail despite his or her best efforts. In Sirius Black's case, he is hot-headed despite his well-meaning intentions. That flaw got him framed for murder, and it eventually got him killed.