It was caught as a Pidgeotto in the Viridian Forest and it was used in some gym battles but always getting hurt badly in the fight.
In Pallet Party Panic, it was used to slash Team Rocket's Meowth Balloon with its Quick Attack to stop them from escaping with Pikachu but Team Rocket has a back up balloon to escape. After Team Rocket is blasted off by Charizard, Ash and the group were heading to the Orange Islands to bring the GS Ball back to Professor Oak as requested on the way. Ash was later attacked by Fearow who leads a flock of Spearow and is the same Spearow that Ash wanted to catch it at the start of his journey who is now evolved into a very ferocious form. With Pikachu's Thunder Shock, Ash lands on the same tree where Team Rocket had landed. Ash manages to let Team Rocket as bait to be chase by Fearow and its flock. He let his Pidgeotto to convince all of the wild Pidgey and Pidgeotto to fly away and it succeeds and Fearow arrives to stop them from flying away as it attacks Pidgeotto and was hurt. As Pidgeotto was desperate to see all the wild Pidgey and Pidgeotto get attacked by Fearow, it suddenly evolved into a Pidgeot. Pidgeot allows Ash and Pikachu to be mounted by it to stop Fearow. It demonstates its powerful Gust and Quick Attack on Fearow followed by Pikachu's Thunderbolt to weaken it. When the Fearow was weak, Ash tried to catch it, but failed to do so. Pidgeot teams up with all the wild Pidgey and Pidgeotto to attack Fearow multiple times making the latter flying away in fear. Ash released his Pidgeot to protect the Pidgeotto and Pidgey promising to come back for it after he delivered the GS Ball, a promise he hasn't yet fulfilled. It is last seen flying with a flock of wild Pidgey and Pidgeotto in the sunset.