Both Dan Duryea and Charles Bickford were considered for the role of "Potter". Although Lionel Barrymore won an Academy Award for Best Actor in A Free Soul in 1931, in the 1940s he was well-known as the voice of Ebenezer Scrooge in CBS radio dramatizations of A Christmas Carol, and is now best remembered for his role as Henry Potter. A wheelchair-user due to a hip injury and severe arthritis, Barrymore played Potter as confined to a wheelchair due to polio. His wheelchair is pushed in all scenes by a wordless assistant (played by Frank Hagney).
Mr. Potter owns the bank and the transportation department in the fictitious Bedford Falls, as well as most of its businesses; the primary exception is the Bailey Building & Loan, in which Mr. Potter holds a minority stake. The Building & Loan is a constant source of aggravation for Mr. Potter, due to its inability to generate profits. As well, the Building & Loan's willingness to offer mortgages that the bank will not means many of the townsfolk leave Potter's rental properties (at times referred to as slums) in favor of people buying houses enabled by low interest loans from the Building & Loan.
Mr. Potter is a large stockholder of the Building & Loan and has a seat on its board, giving him the ability to exert some influence on its operations. He mainly uses this influence to make several attempts to shut it down. He moves to dissolve the Building & Loan after the death of Peter Bailey, but after George Bailey makes an impassioned speech about the necessity of the Building & Loan in keeping Mr. Potter's activities in check, the board votes down the motion on the condition that George stay and run the company. As George and his new wife Mary, played by Donna Reed, start to leave on their honeymoon, a bank run commences, causing George and Mary to return to the Building & Loan. Mr. Potter calls in the bank's loan to the Building & Loan (ostensibly to provide his bank with cash, but also to empty the Building & Loan's coffers) and then offers its shareholders fifty cents on the dollar for their shares in an attempt to become the company's majority shareholder. This attempt is thwarted when George convinces the Building & Loan depositors to take only what cash they need, instead of demanding their entire deposit at once. He and Mary use their honeymoon savings to keep the Building & Loan open and solvent.
In another attempt to weaken the Building & Loan, Mr. Potter offers George a job working directly for him, managing his affairs, at an extremely generous salary, and hints at the possibility of travel outside Bedford Falls, which George has always wanted to do and never has. George rejects the offer after Mr. Potter suggests that it would mean the end of the Building & Loan.
Later, with World War II over and George's younger brother Harry Bailey scheduled to come home as a war hero, Mr. Potter encounters George's Uncle Billy at the bank, where Uncle Billy is making a deposit of $8,000 in cash. Gloating over the success story that the Baileys have become, Uncle Billy accidentally stuffs the cash into a newspaper that he hands to Mr. Potter. Mr. Potter recognizes the mistake upon returning to his office, and keeps the cash, knowing that the bank examiner is at the Building & Loan on a routine visit and the loss of $8,000 will have terrible ramifications for George. George later comes in desperation to Mr. Potter asking for a loan to cover the lost money; instead of returning it, Mr. Potter demands that George show collateral. The despondent George then reveals his sole liquid asset: $500 equity in a life insurance policy with a face value of $15,000. Mr. Potter's response is that George is worth more dead than alive. Exercising what he says is his duty as a Building & Loan stockholder, Mr. Potter then begins calling the police to report George for criminal malfeasance and misappropriation of funds. The defeated George leaves the scene.
Later that night, Potter sees George once more, happy, as if he had never lost $8,000 and was positively overjoyed at the thought of a prison term. "Merry Christmas, Mr. Potter!" he shouts. Mr. Potter responds: "Happy New Year to you too ...In jail!" This is Mr. Potter's final scene in the movie. What Potter doesn't know is that George had just been shown a vision by his guardian angel (Clarence Odbody, played by Henry Travers). George was on the verge of suicide after his conference with Potter and wished that he had never been born. In response, his guardian angel showed him a vision of what would have become of Bedford Falls had George never been born: Potter has taken over the town and renamed it "Pottersville", and it is a sleazy and dangerous place filled with whiskey joints, crime, pawnshops, violence, seedy entertainment establishments, and unhappy people with meaningless, amoral lives. This is the "thrifty working class" Potter had allegedly envisioned years earlier.
When George returns to town, he has triumphed over Potter, because he finally realizes that all he has done for Bedford Falls has made him an important leader of his community, deeply respected and admired. This is evident when most of the town raises a collection to help make up the financial loss, culminating with a massive advance supplied by George's wealthy industrialist friend Sam Wainwright that more than makes up the difference. Even though Potter still remains George's business rival, the townspeople clearly support George rather than him, and it seems certain that the young Bailey will eventually be the more successful.
Mr. Potter ranks at #6 on the American Film Institute's list of the 50 Greatest Villains in American film history. However, others view Mr. Potter as the hero of the film. At the time some in the FBI considered the film's portrayal of Potter as unfair, and in a 2007 article in The Guardian Graham Fuller quotes a 1947 FBI internal memo that states the film "represented a rather obvious attempt to discredit bankers by casting Lionel Barrymore as a 'scrooge-type' [sic] so that he would be the most hated man in the picture. This ... is a common trick used by communists."
- "It's a Wonderful Life", American Film Institute
- Corliss, Richard. "Top 25 Greatest Villains ", Time, April 25, 2007
- Fuller, Graham. "Happy Birthday, George Bailey", The Guardian, December 24, 2007
- Billy Paterson (2006-08-20). "Exclusive: I Was Monty's Double". The Sunday Mail. Retrieved 2007-08-18.
- Joe Rhodes (October 21, 2000). "Flash! 24 Simpsons Stars Reveal Themselves". TV Guide.
- "'Underdog' animator had no fear". Pittsburgh Post-Gazette. Retrieved 12 November 2014.