Ash first saw this Spearow in Pokémon - I Choose You!, where he mistook it for a Pidgey on Route 1 and threw a rock at it to weaken it so he could catch it because Pikachu had refused to battle it. Ash ended up bumping the Spearow's head and angering it. Spearow then attacked Ash and Pikachu along with him because it was jealous of human-trained Pokémon. Pikachu ended up shocking Spearow with ThunderShock and leading Spearow to call on a bunch of Spearow to attack them. They injured Pikachu and came back after Ash fell into a lake. Ash tried convincing Pikachu to go into his Poké Ball, but Pikachu instead rushed onto Ash's shoulder, absorbed lightning and used ThunderShock. They then were weakened by ThunderShock and sent flying.
Ash later encountered Spearow again in Charmander - The Stray Pokémon, where it attacked Damian's Charmander on Route 24, but Ash, Misty and Brock rescued it. Pikachu defeated the Spearow with ThunderShock again and they flew away.
In Pallet Party Panic, It attacked Team Rocket after they fell into a tree full of Pidgey and Pidgeotto that the flock didn't get along with. It then attacked Ash and dropped him in the tree as well. Ash's Pidgeotto then evolved into Pidgeot and defeated Fearow, but he was unable to capture it. However, the Pidgey and Pidgeotto defeated it under the leadership of Ash's Pidgeot and drove it away. Ash left Pidgeot behind to protect the Pidgey and Pidgeotto.
It appeared in a flashback in Lucario and the Mystery of Mew and later in a world connected to the past in Historical Mystery Tour, where Ash was flung into its tail by a Rattata and it attacked him with a flock. Ash and Pikachu (who was supersized), defeated the Spearow and Ash later realized this.