Ash first met Sirfetch'd as a Farfetch'd in Toughing It Out! during a visit to Wyndon after hearing about it from a Trainer whose Chewtle had been defeated by it. As soon as he and Goh encountered it, the latter attempted to catch it but failed, even when trying to battle it with his Kantonian Farfetch'd. Afterwards, Ash battled the Galarian Farfetch'd with his Riolu and managed to defeat it. After Farfetch'd had been healed in a Pokémon Center, Ash saw its eagerness to have more battles and asked if it wanted to come along with him, which it agreed to.
In Trials of a Budding Master!, Ash used Farfetch'd in a World Coronation Series battle against Dozer and his Gurdurr at Rock Tunnel. Despite Gurdurr's formidable physical strength, Farfetch'd eventually emerged victorious, increasing Ash's ranking. Soon after, Ash was challenged by Rinto and his Gallade. Gallade easily dodged all of Farfetch'd attacks before using False Swipe on it, taking it down without actually making it faint.
Farfetch'd and Ash with their Knight Medals
In Searching for Chivalry!, Farfetch'd accompanied Ash to Kalos in order to take on Elite Four member Wikstrom's Castle of Chivalry training course, along with Goh and his Scyther. During the course's second challenge, a booby-trapped maze, Farfetch'd fell into a trap hole, and although Ash pulled it up, it dropped its leek. Ash jumped down into the hole and managed to return the leek to Farfetch'd. In the third challenge, Farfetch'd took on Wikstrom's Aegislash, while Ash himself engaged Wikstrom in a swordfight. When Ash started to get overpowered, Farfetch'd remembered Ash's selflessness while retrieving its leek and defended him from Wikstrom's sword, at the cost of taking a hit from Aegislash's Sacred Sword. However, Farfetch'd was then able to evade a second Sacred Sword using its newly learned Detect. Farfetch'd then followed through by hitting Aegislash with Brutal Swing and was prepared to attack again when Ash told it to stop as Goh and Scyther were able to retrieve the key and win the challenge.
Farfetch'd using its broken leek as a sword and shield
In Beyond Chivalry… Aiming to be a Leek Master!, Farfetch'd battled Rinto and his Gallade in a World Coronation Series match. During the battle, Gallade sliced off the top of Farfetch'd's leek, shocking the Wild Duck Pokémon. Ash was able to overcome this setback by having Farfetch'd mimic Wikstrom's Aegislash and use the cut-off part of its leek as a shield and wielding the remaining part like a sword. With this tactic, Farfetch'd was eventually able to land several critical hits on Gallade and evolve into Sirfetch'd as a result. Despite Rinto having Gallade activate Justified to boost his attack power, Sirfetch'd was still able to overpower Gallade and defeat him, raising Ash's ranking.
In A Battle of Mega Versus Max!, Sirfetch'd was the third Pokémon sent out to battle Bea during Ash's second World Coronation Series rematch against her. It briefly battled her Machamp, blocking a flurry of attacks before outmaneuvering it and dealing damage. Machamp was subsequently recalled for Hawlucha, who easily avoided Sirfetch'd's attacks and defeated it with Sky Attack.
In JN104, Sirfetch'd was the first Pokémon Ash used in his World Coronation Series match against Drasna. Despite temporarily losing its shield and sword, Sirfetch'd was able to reclaim them and deal some damage to Drasna's Noivern before Ash chose to recall it. He later sent it back out to face Drasna's MegaAltaria, whom it was able to defeat with Meteor Assault before succumbing to the damage it had already taken and fainting as well. Despite this, it still reemerged from its Poké Ball to cheer for Dracovish for the rest of the battle.
Personality and characteristics
Sirfetch'd and Ash
Sirfetch'd is a very prideful Pokémon, tending to engage others in battle in order to hone its skills. Even when it is at the brink of defeat, it refuses to give up, pushing its body to the absolute limit. Upon seeing Ash sharing the same battling spirit and passion, it agreed to join his team, after he offered to help it grow stronger, and it immediately resumed training with Riolu after its capture.
As shown in Trials of a Budding Master!, Sirfetch'd, as a Farfetch'd, generally acted cold and aloof towards its Trainer–even attacking Ash with its leek–and was only interested in working towards its goal of becoming a Leek Master. It was even seen rushing into battle against Ash's orders, particularly when it is engrossed in a fight. While its raw power was enough to defeat Dozer's Gurdurr, it was completely outmatched by Rinto and Gallade, who were completely in sync with each other.
As a Farfetch'd, facing its regional form
However, during Wikstrom's Castle of Chivalry challenge in Searching for Chivalry!, Farfetch'd started to bond with Ash when he saved it from falling and retrieved its leek for it. Seeing Ash's selflessness, Farfetch'd later defended him from Wikstrom's sword, choosing his safety over a battle victory. Upon evolving, Sirfetch'd began displaying a much more chivalrous and gallant demeanor, as seen when it protected its Trainer from a puddle being splashed by a passing truck while returning from their battle with Rinto. Its swordsmanship has also become much more precise, to the point where it could use the tip of its leek to slice open a letter, as seen in Thrash of the Titans!.
As a Farfetch'd, Sirfetch'd appeared to have a mutual rivalry with Goh's Kantonian Farfetch'd. While the two are normally friendly to each other, they were prone to bickering, which leads to them clashing with their leeks. In JN103, Sirfetch'd ended up developing a close friendship with Ash's Dracovish, after the Fossil Pokémon inadvertently helped it master Meteor Assault. This was shown again in the following episode, where it came out of its Poké Ball to cheer Dracovish on during a tough battle.