- "You can recognise Snotlout from a mile off by his enormous hairy nostrils, they are GIGANTIC, you could park a Gronckle up there. Snotlout is good at everything and a natural leader. The son of Baggybum the Beerbelly, Stoick the Vast’s younger brother, he is intending to get rid of Hiccup sometime in the future so that he, can become Chief of the Hairy Hooligan Tribe."
- ―Official How to Train Your Dragons Website
As the first part of the Dragon Initiation Program, Snotlout captures a Monstrous Nightmare from the Dragon Nursery, despite a longstanding Viking tradition stating that only the son of the chief can possess a Monstrous Nightmare.
At the Final Initiation Test on Thor'sday Thursday, Snotlout and all the other initiates fail, because no one was able to gain control over their fighting dragons, a fight started by Toothless. The punishment for failure is exile from the Tribe. Snotlout resents Hiccup for this and vows to kill him once they leave the island.
However, the next day after the failed Test and also a huge storm, the Isle of Berk is threatened by several colossal Seadragonus Giganticus Maximus. Snotlout initially refuses to assist Hiccup with his atypical plan, but Thuggory, the Meathead boy who is even bigger than Snotlout himself, threatens him to follow Hiccup's plan. Reluctantly he does so, and he and the exiled initiates save the island and get the banishment rescinded.
Snotlout is listed as a student in the Pirate Training Program in How to Be a Pirate, meaning he participates in lessons such as 'Swordfighting at Sea (Beginners Only)'. During one lesion of 'Swordfighting at Sea', Hiccup volunteers to spar with Dogsbreath with wood-sheathed swords. The fight gets out of hand and the sheath comes off Dogsbreath's sword, and he almost kills Hiccup. Later, Snotlout implies that it was he who removed the sheath, hoping Dogsbreath would indeed kill Hiccup.
- "Adieu, Snotlout. I could not have done this without you"
Showing that Hiccup forgives Snotlout for the years of hatred between them.
Unlike his cousin Hiccup, Snotlout is strong, hearty, and excels at being a Viking. He is rather muscled for his age. He has a very large nose with wide nostrils.
- "Somebody like Snotlout, for instance, was tall, muscley, covered in skeleton tattoos, and already had the beginnings of a small moustache. This consisted of a few straggly yellow hairs clinging to his upper lip and was deeply unpleasant to look at, but still impressively manly for a boy not yet thirteen."
- ―How to Train Your Dragon
He is mentioned several times as looking like a pig, possibly due to his large snout.
Snotlout is good at all the lessons in the Dragon Initiation Program and the Pirate Training Program. He excels at being a brutish belligerent Viking and great at insulting others, which is ideal in his world.
- "Snotlout was a natural at Mindless Violence, superb at Advanced Rudery and practically everything else."
- ―Book 2
Snotlout is also excellent at swordfighting, even fending off adult Outcasts who are much larger and experienced than he, in How to Be a Pirate. He also won a Black Star - one of the highest medals of honour and bravery in the Hooligan Tribe - for helping win the battle.
Snotlout is a bully, fully adhering to the survival of the fittest attitude of the Vikings - only the strong can belong. He is extremely competitive, but also feels pressure to be noticed, as he is only the second in line for the chiefdom on Berk.
Snotlout hoped to be the chief of the Hairy Hooligans one day despite the fact that Hiccup was the true heir; however, if something were to happen to Hiccup, Snotlout would've been next in line for the position. The two were well aware of this fact which spawned a hatred between them. However after his death Hiccup forgave Snotlout for the years of hatred between them. Hiccup even tells the tribes of the archipelago on the Island of Tomorrow of Snotlout's sacrifice.
Snotlout's father Baggybum was always very proud of his son for always being the best of the young Vikings. But after Snotlout betrayed his tribe and joined Alvin and his mother, Baggybum became very disappointed in his son, as seen in the Amber Slavelands. Though after Snotlout's sacrifice, Baggybum once again became proud of his son for his redemption.
Dogsbreath and Snotlout have a good relationship - that of leader and follower. Dogsbreath is his loyal sidekick and often does his bidding such as beating up someone, which Dogsbreath enjoys anyway.
- "What is it, Hiccup? A brown bunny rabbit with wings? A flower fairy? A fluffy flying frog?"
- ―Speaking about Toothless in Book 1
- Though Snotlout and his film counterpart have many similarities, they also have many differences which include:
- The fact that in the franchise, Snotlout doesn't really hate Hiccup, he just looks down on him and mocks him, and at the end of the first film the two even become friends. While in the books Snoutlout legitimately hates Hiccup and wants him dead. Though this is resolved in the final few chapters of How to Betray a Dragon's Hero.
- Unlike the franchise, Snotlout and Hiccup are in fact cousins.