Although Waternoose is an antagonist in this movie, he has a gentle, fatherly facade and is only driven to villainy out of desperation to keep Monsters, Inc. afloat in the midst of the energy crisis. He becomes more villainous as this drive and desperation strips away his morals and he is determined to not let anything stop what he thinks will be the best way for the company to keep going, never taking into account looking for other energy resources.
Waternoose is an obese gray monster, completely bald, with 5 eyes, and walks around on a set of six crab-like legs, he is always seen wearing a black tuxedo jacket over a white shirt, a red vest, and a black bow tie. When he was younger, he had an Afro-style hair and a chinless beard. A producer described him as a "cross between a spider and a crab".
Mr. Waternoose was troubled that his company was starting to fail, because more and more kids were not fearing monsters, and therefore, the power used to power the city was being decreased. When a child was let in or has touched a monster, the door must be shredded, and losing power was no good. Randall agreed that if he was given control over the company afterwards, he'll help Mr. Waternoose with his power problem. So, Randall worked overtime one day and accidentally left the door to the child he was going to steal exposed to Sulley (whom at the time had stayed behind to file Mike's paperwork when he forgot to do so before his date). Sulley opened the door by accident, and the girl was let loose.
He was going to appear in the prequel, and he was going to be voiced by Kelsey Grammer. But this was dropped at the last minute. After Mike and Sulley begin their new jobs at Monsters, Inc., they eventually work their way up to the position of the scaring team job that they have in the first film. This is revealed to the viewer when Mike's MI locker shows photos of them beginning this job and shaking hands with Mr. Waternoose. This is likely when the bond between him and Sulley began to grow. In the photo, he sports an afro and a chinless beard which he lost sometime before M.I.
He is first shown at the very beginning of the film, informing Thaddeus Bile and the trainees about the dangers of a human child after Thaddeus has unsuccessfully attempted to frighten a simulation child in bed.
Later, when Sulley and Mike, were carrying Boo, they attempt to alert Henry J. Waternoose, while he is attending a training session for new monsters. However, Waternoose asks Sulley to demonstrate his scare tactics, and when Sulley growls loudly, Boo reveals herself as a human child. Waternoose, taking Boo, promises to set things right, but instead reveals he is in on Randall's scheme, worried for the future of the company. He brings a door from the vault and pushes Sulley and Mike into it the door takes them to the Himalayas in Nepal. Sulley and Mike have a falling out. Sulley, only concerned about getting to Boo quickly scavenges parts from stockpiles from the Yeti, another exiled monster, and returns to the nearest village to use a door and return to Monsters, Inc.
Inside the secret lair, Mr. Waternoose accepts Randall's evil plan and watches as Randall and Fungus begin to test the scream extractor from Boo. Sulley intervenes at the last moment before the Scream Extractor gets to her mouth, dismantles the device, throws it at Mr. Waternoose and Randall, and rescues Boo. Mr. Waternoose then orders Randall to stop Sulley and finish him off, but Mike, who has followed Sulley back into the Monster World, accidentally gives away Randall's cloaking abilities, allowing Sulley to knock Randall off him by punching him in the face. After Sulley, Mike, and Boo escape, Mr. Waternoose tells Randall that they can't let any witnesses be exposed.
While Sulley and Mike lead Randall on a wild chase through a large chamber where thousands of doors to the human world are kept, Mr. Waternoose rallies the CDA to capture Sulley, Mike, and Boo under the pretense that they are the criminals responsible for the entire incident.
After the trio defeat Randall and return to Scare Floor F which is packed with CDA agents, Mike distracts the CDA by driving them away while Mr. Waternoose catches sight of Boo with Sulley and gives them chase to a simulation room.
Mr. Waternoose breaks into a room where Sulley has went into and confronts Sulley, declaring that he'll kidnap a thousand children before he lets the company die. Knocking Sulley out of his way, he tries to grab Boo from the bed, but he instead grabs the simulation child. Just then, the wall goes up to reveal that Mike is behind the controls. Mike, who has recorded the confrontation between Mr. Waternoose and Sulley, plays back his favorite part to reveal Mr. Waternoose's nefarious scheme to the CDA as Mr. Waternoose watches in bewilderment. With this incriminating evidence, the CDA turns on Mr. Waternoose and arrests him. As he is being dragged away, Mr. Waternoose angrily blames Sulley for "destroying" Monsters, Inc. and making the energy crisis worse. It seems to be a lose-lose scenario when Sulley realizes how true it is, until Mike leads him to realize that laughter can put the company back in business, which it does, as laughter is proven to be ten times more powerful than scream. With this, Sulley is made the new CEO of Monsters, Inc. and it can be assumed that Waternoose regrets his actions when he hears about the company's rebound in prison.
- Mr. Waternoose is the last animated character voiced by James Coburn before his death.
- Although Waternoose ended up becoming involved in abducting Boo despite his claims of children being toxic to monsters, it is never made clear whether he knew children were not toxic, and thus lied about their danger to the monsters, or if he did truly believe they were toxic, but felt saving the company from bankruptcy was worth the risk of being poisoned by a child and potentially killed.
- Waternoose's true nature is revealed near the end of the film when Mike records him on TV.
- Waternoose was originally going to be voiced by Kelsey Grammer in Monsters University, but he was dropped out for unknown reasons.
- In some ways, Waternoose appears to be the complete opposite of Dean Hardscrabble: while Hardscrabble appears stern and unpleasant but is actually caring and benign, and is therefore an ally to Mike and Sulley in the prequel, Waternoose appears friendly and kind-natured but is actually cruel and evil, and is therefore an antagonist of the first film.