Years after botching a public address and live radio broadcast in 1925, Prince Albert (COLIN FIRTH) still suffers from a bad stammer that leaves him quite uncomfortable making public appearances. His father, King George V (MICHAEL GAMBON), has no such problems, but laments that the relatively new broadcast medium means he and other such figures must now become actors. But at least he doesn't have to worry about Albert succeeding him since he has an older son, Edward (GUY PEARCE), who's well-groomed for the role, even if he wants nothing to do with that.
Albert's wife, Elizabeth (HELENA BONHAM CARTER), however, hasn't given up on him and thus continuously tries to find someone who can help. She thinks she might have found that person in Lionel Logue (GEOFFREY RUSH), an Australian speech therapist known for his unorthodox treatment procedures. Working from his home office where he lives with his wife, Myrtle (JENNIFER EHLE), and their kids, Lionel eventually convinces Albert to do as he says, and that helps alleviate some of the problem.
Yet, there are other issues Albert must contend with, including the death of his father and then Edward abdicating the throne in order to be with the love of his life, married American commoner Wallis Simpson (EVE BEST). Having succeeded his brother and now known as King George VI, the monarch must also contend with the rumblings of war and his dealing with Winston Churchill (TIMOTHY SPALL) in such matters. With war with Germany imminent, the King must prepare the biggest speech of his lifetime, something with which only Lionel can assist him.