Ash caught it as a Starly in Two Degrees of Separation while searching for Pikachu, who was missing due to the antics of Team Rocket. Aipom was swinging through the trees and accidentally bumped into Starly, so the two Pokémon battled. Weakened by Aipom, Starly was captured and immediately used in the search for Pikachu. In When Pokémon Worlds Collide, Starly had his first battle against another Starly belonging to Paul and lost.
In A Staravia is Born, Starly evolved into a Staravia during a battle with Team Rocket. Immediately after his evolution Staravia had perfectly learned Aerial Ace. Evolving has also allowed it to grow much stronger and become very useful in searches.
Staravia was the only one of Ash's Pokémon who didn't participate in Ash's first Sinnoh Gym battle against Roark; however, Staravia helped out in Ash's second Sinnoh Gym battle, defeating Gardenia's Cherubi. After seeing Reggie's Staraptor use the powerful Brave Bird attack, Ash was inspired to teach it to Staravia. In the third Sinnoh Gym battle, Staravia defeated Maylene's Machoke and Meditite, as well as successfully mastering Brave Bird.
In Pursuing a Lofty Goal!, a PokéRinger competition was held in Squallville where Ash entered and won with Staravia, who evolved into a Staraptor in the process. Shortly after his evolution, Staraptor learned Close Combat and defeated Paul's Honchkrow, earning Ash his first victory over Paul.
In Sliding Into Seventh! he was used in the Gym battle against Candice, where he was easily defeated by her Abomasnow after winning against her Medicham.
It battled in Ash and Paul's full battle in Pedal to the Mettle! where he went up against Torterra and Weavile. He managed to defeat Weavile, despite the type-disadvantage. In Evolving Strategies! he also fought against Paul's Ursaring, but lost quickly.
Staraptor was used in League Unleashed! against Nando's Roserade. He was able to defeat it with a powerful Brave Bird attack, but was defeated by Nando's powerful Armaldo.
In Familiarity Breeds Strategy!, he was used against Paul's Gastrodon. Ash realized that Paul's Gastrodon could use Counter Shield, and Staraptor was hit by the technique. When Gastrodon slammed him on the ground, he managed to use Close Combat on the ground to get away, but was hit with an Ice Beam in the process. He started to show signs of tiring, so Ash decided to recall him in place of Buizel. Later on in A Real Rival Rouser!, after Buizel fell to Paul's Drapion Ash called him out again. However, he was unable to triumph against the superior power of Drapion's Cross Poison and Toxic Spikes.
It is assumed that Ash left Staraptor at Professor Oak's Laboratory when he decided to go to Unova.