This actor's name is Mark Hamill, a man of multiple talents whose work in film and animation made him a cult icon.
Like many, I was introduced to Hamill by way of "Star Wars," when he played a certain Tatooine farmboy turned Jedi Knight named Luke Skywalker. Most people say that Hamill doesn't fare as well, acting-wise on camera, but "Star Wars" catapulted him into stardom. Actually, the reason we become so compelled with Luke's coming-of-age journey is because of Hamill's performance. From "A New Hope" (technically the first film, but Lucas wants it to be considered the fourth) to "Return of the Jedi" Hamill displays growth from rashness and overeagerness to wisdom and maturity. His chemistry with Harrison Ford (Han Solo) and Carrie Fisher (Princess Leia) is also a selling point of his performance. Equally compelling are his scenes with Yoda. While I don't hate the "Star Wars" prequels by any means, I did notice some cases where the live actors were staring through the CGI-created characters. The problem does not apply with these three movies, partially because Yoda graces the screen with gusto, but also that Hamill interacts with the little green imp as though he's actually THERE. And that is a huge testament to acting. Some might find his "NOOO!" scream in "The Empire Strikes Back" a little over-the-top, but otherwise these three films show that he is underrated as a screen actor.
I admittingly have never watched much of the "Batman" animated series, but I did admit to seeing the forgotten feature "Mask of the Phantasm", in which Mark voiced the Joker. It's been a while since I've seen that film, but I remember being surprised at how different it was from Luke.
Where Hamill really earned my respect was through his voice acting in two movies from Hayao Miyazaki, "Nausicaa of the Valley of the Wind," and "Castle in the Sky." The latter film features Mark in what may arguably be one of his finest performances since "Star Wars." He plays the main antagonist, Colonel Muska. It was through this role that Hamill surprised me. His vocalization of Muska is alternatingly seductive and maliciously insane--and strangely, the character bears a resemblance to the actor himself. From the moment I found out Hamill was cast as Muska, I figured it would be a cool choice, but he went way beyond my expectations. He also has quite a frightening, chilly laugh. (Some people have pointed out that toward the end, Hamill's Muska occasionally shows flashes of his "Joker" voice; considering that Muska goes crazy at the finale, it's strangely fitting.) Although derided by a vocal minority of naysayers or fans of the original Japanese, Disney's dub of "Castle in the Sky" has still managed to carve a following; Hamill's Muska contributed greatly to the success of the dub. (Not to mention Cloris Leachman as the pirate captain Dola, her boys, the military, and the miners. The leads are only OK, but that's another issue.)
Love or hate the dub, Hamill's performance as Muska drew raves; so much so, in fact, that he was chosen to voice another role in Miyazaki's "Nausicaa". Here he plays the Mayor of Pejite, which is a smaller role, and, incidentally, not so villainous. But this is how it should be; the Mayor is not an evil man, he is simply misguided. So Hamill doesn't give the Mayor the villainous edginess he supplied Muska. Regrettably, since his role in the dub is smaller, Hamill's work here is less remarkable than in "Laputa", but who wouldn't want to hear this talented man in another Miyazaki dub?
And now? Hamill has done other Anime--"Robotech". I have yet to hear this role, but I do hope that he continues to get more voicing in Anime dubs. Considering how talented he is as a voice actor and the amazing vocal range he displays, it's not hard to see why Hamill is highly regarded as one of the best in Hollywood's voice artists. His live-action work probably isn't as remarkable (unless you count "Star Wars"), but the man is a genius.
Use the force, Mark.