Clint Eastwood did not receive an Oscar nomination for portraying "Joe" in A Fistful of Dollars.
Well I will just mention that Toshiro Mifune played the wanderer in Yojimbo, and that he gave the .....(that will have to wait for another time). Clint Eastwood made his debut as a leading man here in his most famous role as the man with no name. The man with no name is technically incorrect in that he is called a name in all three of the dollars films, but technically his name could be entirely made up by those who refer to him as such. Although all three films are the man with no name trilogy this is the only film where Eastwood has to carry the film alone. In For a Few Dollars More he had Lee Van Cleef as a vengeful bounty hunter with him and in The Good the Bad and the Ugly Eli Wallach's talkative Tuco was always there, but here he flies solo.
Eastwood because he is alone actually has a somewhat different role than the one he would eventually take in the later two films. In both of the sequels Eastwood is almost straight man in the role and is a great foil for both Van Cleef's and Wallach's performances in those films. Eastwood is by himself though and where the other two film the more emotional parts tended to go to Van Cleef and Wallach it is Eastwood who actually has bring the emotional weight in this film. This is not to say though that Bill is that different form Monco and Blondie in terms of conception, but there is a reason why Joe does not end up with any money in this film and left with fortunes in the later two films.
Most of the performance though is Eastwood doing the Man with no Name which is that of a cool calm killer who deals with his enemies with precision in both out smarting them and out shooting them. Eastwood is one of the very best at being the stern and quiet killer who never blinks, only squints when he kills several men in quick succession. Eastwood just is cool in the role and he absolutely makes it all work with his strong presence and very particular way of reacting. Every little look and twitch with his head are always great as in his silence Eastwood. Eastwood pulls an interesting trick in that he portrays the killings usually as run of the mill, but never does he make Joe seem cruel or psychopath in doing so.
Eastwood avoids making the Man with No Name seem a psychopath for two reasons mainly. One Eastwood is just about always charismatic in his Clint Eastwood way, but also importantly in the few line deliveries that Eastwood is allowed through the film. All of the lines are pretty to the point and Eastwood delivers them all with as much precision as Joe does when handling his gun. Eastwood brings the right sly attitude with Joe that brings a nice bit of humor to the film as pretty much every fight can end with at least a bit of chuckle because of either the deadpan way he delivers one of Joe's quips or simply because of the equally deadpan way that Eastwood makes Joe react to a situation.
There are a few serious moments though in the film where Eastwood actually must bring a greater emotional weight to the proceedings than what is standard for Clint Eastwood. These still rather brief moments involve either Joe's reaction to an unfortunate woman in the middle of the conflict, or just at the evilest actions committed by the main villain of the film Ramon (Gian Maria Volonte). These moments are to the point so Eastwood basically gets to the point shifting to a more reflective Joe quite effectively and it feels completely natural for Joe to have this more somber moment. Eastwood never overplays the lighter antics so he can go heavier with ease and really give the moment impact, just like he later in the bridge scenes of The Good the Bad and the Ugly.
This is of course a good performance by Clint Eastwood one that is a completely assured leading performance despite this being his first major film role, but it is obvious why this film propelled him to super stardom. Where Eastwood settled into a slightly more passive role of sorts in the two sequels that nicely amplified the power of Wallach's and Van Cleef's performances, but the first time he played the part he proved that he could go in alone as well. This is not Clint Eastwood's greatest performance but it is an excellent example of exactly what makes Eastwood such a strong actor since he can carry a picture so well and so smoothly in his trademark fashion which he established here.