One of Doris Walker's responsibilities at Macy's in New York City is to organize the famed annual Macy's Thanksgiving Day Parade, which marks the official start of the Christmas season. She is a realist, that attitude toward life due to her own failed marriage not being the fairy tale she envisioned it would be. She has taught her impressionable six-year-old daughter, Susan, the same thing. Susan does not believe in make believe or the "fantasies" associated with Christmas, such as Santa Claus. At the last minute, Doris is forced to hire a replacement Santa for the parade, not knowing anything about him besides him looking the part. He is such a success that she hires him to play Santa in the main store for the remainder of the Christmas season. It isn't until he becomes an invaluable addition to there, including coming to the positive attention of Rowland H. Macy himself, that Doris learns that he calls himself Kris Kringle and truly does believe he is the real Santa Claus. At this point, Susan, witnessing things she can not explain rationally, begins to wonder if he is who he says he is. To protect herself and the store, Doris, without telling Kris what she is truly doing, makes him go through a psychological evaluation through the store's therapist, Granville Sawyer, who wrongly believes he's God's gift to his profession. Because of their antagonism toward each other, Granville tries to have him committed, which leads to court proceedings as to his sanity. Doris' neighbor, Fred Gailey, who is attracted to her, takes his case, in part to be close to her, but also to help him who he believes is just a kindly and harmless old man. Fred's defense is to prove that Kris is Santa Claus. In the process, he wants more than anything to make both Doris and Susan believe in faith, for Doris again and for Susan the first time in her life.