The one-legged Viking also has immense talents as a blacksmith. Having been seen as too scrawny and weak to go out on the battlefield, it was thought best to keep Hiccup indoors where he could avoid causing any trouble, leaving him to become Gobber's apprentice in the forge. He's there that he learned how to make sure of his actual talents and skills, training to be able to come up with his own designs and inventions. While first making attempts to build weapons to fight off the dragons, when he comes to terms that fighting isn't his preference, he finds more success in designing and creating things of the more useful sort, such as buildings and contraptions that help benefit the village in living alongside dragons ("We have custom stables, all-you-can-eat feeding stations, a full service dragon wash. Even top-of-the-line fire prevention, if I do say so myself."). He's also shown his skills in creating and sewing clothing, having first made a rider's vest when beginning to ride Toothless and eventually creating his famous flight suit, having many useful attachments (spare sheets of blank pages, a compass, and a sheath for a small knife to name a few), as well as leather wings to help him glide in the air with Toothless.

Work as a blacksmith is made easier by his impressive observation skills, such as how he manages to create a tail and saddle for Toothless based on studies of understanding the dragon anatomy and flight skills. He also continues to observe dragons in order to create "Inferno", a fire sword that makes use of Monstrous Nightmare saliva and Hideous Zippleback gas to convince dragons he means them no harm ("Once they see you as one of their own, even the testiest dragons can be trained, right, bud?"). Yet despite making a weapon, which he does hold out in self defense on occasion, he never actually makes use of it in battle, never once using it to harm anyone, confirming Hiccup's eagerness to avoid violent confrontations.