Ulrich Mühe plays Wiesler who we are introduced to as a member of the secret police while he conducts a class to young recruits in training. He is instructing the class through the use of recording of his own successful interrogation of a man accused of being an enemy of the state. Mühe is fantastic in the way he instantly establishes Wiesler's nature at the beginning of the film. Mühe portrays him as the strict authoritarian perfect for his position as a Stasi agent. In the interrogation scene Mühe carries himself with such a striking coldness. There's no sympathy in his eyes just a piercing gaze as he stares right through the man who is he is quickly breaking down under his scrutiny. Mühe keeps a similar reserve in the classroom as he teaches the students with the same strict professionalism. He's particularly good in the quick moment when one student voices dismay at the interrogation and Mühe portrays the lack of hesitation as Wiesler puts a mark next to the students name to keep record of such a remark.
Mühe in addition to this portrays Wiesler as an extreme introvert. Mühe seems to keep everything strictly calculated within Wiesler as even the way he walks seems to be something specific and coded for his own protection. In these early scenes Mühe makes Wiesler basically the perfect tool for such a regime that wishes for mindless devotion and service without a hint of individual thought. Mühe plays Wiesler as barely a man, but rather just a cog in the organization. There's nothing particularly human about he does and there is almost no emotion in him as he performs his duty. Mühe rather brilliantly creates a man, who already would have trouble interacting with the outside world, being only shown a certain way of life that prides itself in constant suspicion and secrecy. Mühe gives us such a man, and he's particularly great in his interactions with his superior. Although they technically are suppose to friends Mühe still shows Wiesler never losing sight of his task as he only seems to interact when its his turn to advise on policy.
Wiesler is released from his oddly sheltered life though when he is assigned to monitor a seemingly apolitical writer Georg Dreyman (Sebastian Koch). At the beginning of the surveillance Mühe keeps Wiesler still very much the operative he should be. As he initially bugs the house Mühe portrays Wiesler going about his job with the utmost precision without a hint of feeling as he makes preparations basically to ruin someone's life. This disregard for a normal humanity continues as Wiesler begins his routine of listening in on Dreyman's life basically just waiting until there is something for which they can arrest him for. Mühe not only portrays a lack of empathy in Wiesler but even a certain venom in the man's mind as though Wiesler just desires to see this enemy punished. While the monitoring continues we are given a glimpse of Wiesler's personal life, or more correctly the lack thereof. Mühe is very honest in portraying Wiesler very much out of his element in the real world, and suggests just a sad lonely man waiting until his next monitoring session.
Wiesler though does not stay on this course though as he learns that the real reason for the inquiry into Dreyman is his relationship with an actress Christa-Maria Sieland (Martina Gedeck), who is lusted after by a powerful official. Mühe does not portray the malice as suddenly leaving Wiesler though as can be seen when he purposefully causes Dreyman to see Christa-Maria being used sexually by the official, and in that moment Mühe keeps that disregard for anyone. The exposure of normal interaction between people, opposed to interrogating prisoners and spending time with other similair individuals, something seems to happen in Wiesler. Mühe's performance technically becomes almost dialogue free as there are large stretches of the film where we just see him listening to Dreyman's life and file the proper reports about what he hears. Mühe manages to make something so compelling though merely through his almost silent reactions as the monitoring continues. Mühe's performance though is particularly effective because the change in Wiesler is so delicately handled.
Mühe is outstanding by showing the process of Wiesler's growing involvement. At first, after he loses his callousness, Mühe does suggest an investment but with a certain distance. Mühe conveys the interest in Wiesler not to be that of one human being caring about another, but rather at first as though Wiesler is merely listening to an interesting story on the radio. Mühe though slowly grows this fascination in Wiesler which seems to become stronger as it is his only true contact with the outside world, the most we see of Wiesler in a personal setting is having sex with a prostitute. Mühe is great in that scene though by rather honestly showing the desperation in Wiesler to reach out, as he asks the prostitute simply to spend more time with him, and Mühe makes it particularly understandable why he would be caught up in Dreyman's story. The greatness of Mühe's performance is the natural and extremely subtle way though he shows the slow change as he continues to listen even when it becomes obvious that Dreyman will be committing an act against the state.
What is so remarkable about Mühe's work is that he earns every moment of Wiesler somewhat improbable transformation. Mühe not only make Wiesler's growing empathy believable. Mühe is wonderful as he expresses the heartbreak, perhaps better than actually suffering the heartbreak, as Wiesler hears about the losses in Dreyman's life. The scene where Dreyman plays a song for his friends death is made most moving not through what Dreyman does, but just Mühe beautiful reactions as he shows Wiesler being truly changed by what he hears. Wiesler becomes so involved though that he even makes contact with Christa-Maria in a bar. Mühe shows Wiesler put on a slight act as though he is just fan, but portrays such earnest emotion as tries to propel here out of despair. Wiesler's investment though causes him to hide Dreyman's activities and Wiesler himself comes under suspicion. To prove his loyalty Wiesler has to interrogate Christa-Maria to find the whereabouts of Dreyman's hidden typewriter. Mühe is perfect in this scene as he partially returns to the old Wiesler to interrogate, but with a noticeable and powerful difference. Now you see in his eyes how it shames him to have to break her especially since she obviously remembers him from before. I love this performance by Ulrich Mühe as his quiet work is what makes the film work. He creates the portrait of such a man finding humanity both convincing and poignant.