Tim Holt did not receive an Oscar nomination for portraying George in The Magnificent Ambersons.
Tim Holt, best known as the far less greedy miner in the Treasure of Sierra Madre, once again plays a role that seems thankless to the showier roles given to much of the cast. Holt plays George who will inherit what is left of the Amberson fortune. Holt in the early scenes plays George extremely straight as the lead character in a family drama like this, really in pretty much the way these sorts of characters are portrayed in parodies. Holt speaks every line as to the point as possible, and in all honesty is quite bland as George seems to just enjoy his status in life as well as the fact that he seems primed to marry his romantic interest Lucy (Anne Baxter). Although I think this was a purposeful directing choice on Welles part, Holt does not find any wiggle room to do something special within his restriction like say the way Daniel Day-Lewis eventually would in A Room With A View.
The reason George just seems the romantic hero is that Welles obviously wanted to give us this golden age appearance for the family of the Ambersons as well as for the life of George. This is torn down rather quickly though when a scandal arises surrounding George's mother and Lucy's father. This leaves George to confront it in a particularly selfish and fairly extreme way showing him to be actually just really a spoiled brat more that anything. Holt again keeps it incredibly straight to almost the point of parody as he plays George's reaction as basically just a temper tantrum. Again I think this does fit the character, and Welles's intent but Holt's performance does it in a particularly standard fashion. His George is just extremely likable Holt suggest no real substance to this, he does it with no style, and never attempts to do it in cleverly humorous fashion either.
Eventually, well rather quickly due to the brevity of the film, George falls on some hard times himself losing Lucy, having to get a job and eventually getting an automobile accident. Again Holt just stays quite bland and very uninteresting. Holt still keeps George as a man of no depth even when distraught, but I suppose that is true to form. Nevertheless George is still one boring man who I could care less about, and Holt does not even turn that into some sort of compelling anti-charisma. Holt's performance and George as a character just seems there to facilitate the more interesting characters who are performed by the likes of Agnes Moorehead and Joseph Cotten. This not a truly bad performance as I do think technically Holt fulfills his duty in a certain way, but that way is particularly forgettable.