Rex Harrison did not receive an Oscar nomination for portraying Daniel Gregg in The Ghost of Mrs. Muir.
Rex Harrison is the titular ghost of the film, and for the first twenty minutes we do not see him only rather are we alluded to his presence. At most we hear of him is a fierce haunting cackle of the apparition.This is until he finally confronts Mrs. Muir directly one night in full view, and we find out the true nature of the ghost. Well it turns out that the ghost is not nearly as scary as the haunting earlier might have suggested being in no way an evil spirit. In fact the ghost of the sea captain Daniel Gregg is quite down to earth for something of his sort anyway.
Rex Harrison is excellent here, and his style of acting is a perfect fit for this film and the role of Daniel Gregg the ghost. Although he is properly spooky and scary in his early laughs but the moment he finally starts talking he eases into the rather casual tone of the ghost well. Harrison is terrific here because he just does not simply stop being a ghost, he effectively conveys an otherworldly quality to his stares and manner particularly in the first time we see his face, but he always humanizes Gregg at the same time. Rex Harrison's casual fashion of acting is perfect in expressing just how human Gregg is.
When Harrison is telling about Gregg's whole haunt is just to keep people out of his home, and that he really did not commit suicide but rather just accidentally kicked over a kerosene later he does it all in a distinctly non ghostly manner. He is instead quite matter of fact so matter of fact that he is actually quite amusing. He does not show any real anguish over his death, the sort of man the Captain is he shouldn't, but Harrison amusing portrays it as a low key annoyance over more of the perception of him after his death more than the death itself.
Harrison portrays the part of Gregg as an old sea salt in his manner and accent, and I must say that he does it pretty well. Although his accent is not always especially consistent it does help in expresses just who Gregg was before his untimely demise. Harrison has just a great deal with the mannerisms and the sometimes crudeness of Gregg who inherited it from being a sailor in life. Harrison gives no apologizes for his character's behavior, and clearly shows that Gregg is perfectly happy with the sort of man he is. He was a man's man, and Harrison shows that the Captain is proud of it.
Most of the film though focuses on the Ghost's relationship with Mrs. Muir. Tierney and Harrison have a nice chemistry here, and their dynamic works well for the film. Her showing at first a great deal of amazement, but Harrison showing Gregg being slightly impressed by her, but mostly just bemused by her company. They play off each other well as they make various trades to allow her to live in his home, but in turn he will stop being a haunting nuisance. It is a most comedic dynamic at first and Harrison's playful performance plays off Tierney's straight one well.
Slowly though their relationship does grow as they come close in their schemes together. Harrison eases into a transition of Gregg being just a little bit amused by her, but than slowly falling in love with her. Harrison effectively shows a hesitation though in Gregg affections he gains slowly. This is not from the Captain not being sure of his love or anything similar, but Harrison bluntly shows that all Gregg is doing is being a bit angry that he cannot go any further because well he is a ghost after all.
After the seem to slowly drift apart due to their living and dead difference, Harrison carefully brings back the mysterious quality he had at the very beginning of his performance. He eases back into it sadly showing the realization of Gregg that his time with Mrs. Muir has passed. Harrison portray of the Captain's final goodbye is particularly moving as he honestly brings to life both the genuine affection the Captain feels for her, but as well he conveys the force that separates the two of them. It is a heartbreaking moment, and effectively makes the ending all the more joyous. This is a very strong performance by Harrison who finds perfect tone for his performance that easily could have been played too much for laughs, or taken the material too seriously. Harrison knows just how to play him in this very likable and entertaining portrayal.