During his travels in the Orange Islands in Snack Attack, Ash discovered an orchard that was under attack by a Snorlax that was eating everything in sight, and was consuming many of the nearby islands vegetation within days. Ash, Misty, Tracey, and Jigglypuff eventually managed to stop the Snorlax. This gave Ash the perfect opportunity to catch Pokémon for his own.
Ash kept the Snorlax on his team for the remainder of his time in the Orange Islands, but could not use it in the finals due to the fact that it would not wake up and needed to be switched with one of Ash's 30 Tauros. After the tournament was won, Ash then decided to keep his Snorlax at Professor Oak's permanently because he could no longer feed it and only called upon its power in major battles.
Since then, Snorlax has become one of the senior members of Ash's team, along with Charizard and Pikachu and has provided much needed comic relief in many situations. Ash called upon it for the Sumo Conference, winning the subsequent fight as a result, and later used it to defeat Clair's Kingdra in their rematch. He also used Snorlax during the Johto League competition, first against Gary Oak where it quickly defeated Gary's Nidoqueen and Arcanine, but lost to Scizor. Snorlax then fought during Ash's following match against Harrison and it defeated Harrison's Steelix and Hypno, though in the end it fell to his Houndoom. Most recently, Snorlax helped Ash earn the Guts Symbol from Greta in Wheel of Frontier by defeating her Hariyama with an Ice Punch and literally flattening her Medicham with Body Slam.