Ash used Gliscor to battle McCann's Scizor and began learning Giga Impact and stayed there to train with McCann.
Ash summoned Gliscor from McCann in order to battle Paul in the Sinnoh league. Gliscor had perfected Giga Impact and while training with McCann, learned Stone Edge. During Ash's battle with Paul, Gliscor battled Ninjask but was unable to overcome Ninjask's speed and was recalled after Ninjask knocked it into the ground, causing it to become poisoned by Drapion's Toxic Spikes. Gliscor later battled Drapion and defeated it using Fire Fang. However due to its exhaustion and the fact that it poisoned, Gliscor was defeated by Paul's Electivire.
After the Sinnoh League, it was a mystery if Gliscor stayed with Ash's other Sinnoh Pokémon or if it went back to McCann for more training until the last episode of the Pokémon Black and White saga where it was shown to be staying at Professor Oaks.