Brendan Gleeson is a consistently competent character actor in supporting roles, but I must say that his true calling is leading man. Two directors who seem to understand that are the McDonagh brothers as Martin McDonagh allowed Gleeson show his considerable talent in In Bruges, and Martin McDonagh brother John Michael McDonagh allows Gleeson to do it once again in this film. The Guard and In Bruges clearly are related in that they both share a certain style which never forgets to be funny while still telling a fairly or very dramatic story.
Gleeson portrays the lead in both films, and his role here as a Sergeant in the Irish police force differs from his role from Ken in In Bruges in the amount of humor in the performance. There was plenty of humor of course in his great performance in In Bruges, but Gleeson does not stop being funny here as the odd Sergeant Boyle. Gleeson has a rather strange way of playing the Sergeant in that he both seems rather serious sometimes in his deliveries which is full of conviction by Gleeson, but Gleeson never stops playing up the humor of the role as well.
Gleeson has just a jovial presence that never stop giving when it comes to giving out laughs through his delightful characterization. Gleeson timing is marvelous here as he rings out each one liner right after the other with marvelous aplomb that never gets old. Gleeson has a great deal of fun in the role in just playing up the central idea behind Sergeant Boyle which is that he either is really dumb or really smart. Gleeson is effective in that he really plays it both ways having constant comedic moments in the rather stupid things espoused by Boyle constantly, yet at the same time Gleeson in his eyes seems to say that Boyle always knows what he is doing.
This is not nearly as complex of a role as Ken in In Bruges and most of it is just being funny, but there certainly is not a problem with that because Gleeson is quite good at it. He plays every scene with the same wonderful comic timing, and plays off well against every other cast member especially Don Cheadle as the straight laced FBI agent. The two play off each other wonderfully with Cheadle playing up just how taking aback the FBI agent, and Gleeson going as far as he can without going too far with his portrayal of this absurd man.
Although almost the entirety of this performance is comedic Gleeson as he did in In Bruges balances it well with an actually grounded characterization. Even though he is always trying to be funny he never comes off as unrealistic because of the perfect tone Gleeson finds in the character. This allows for the few entirely dramatic moments such as when Boyle visits his mother to be properly moving despite being relatively small aspect of the film. Gleeson never falters once always being funny but whenever the need comes to it he is absolutely emotionally convincing as well. Gleeson always shows absolute devotion the the role, and makes Sgt. Boyle a compelling if odd hero to follow. Gleeson makes this just a very entertaining from beginning to end through his realization of a man who may be the best and worst cop simultaneously. This may not be his very best work, that would be In Bruges, but still is great work from this actor who deserves more leading roles to his name.