Pipsqueak, bearing a misnomer for his name, was the largest and, physically, the strongest member of the Freedom Fighters, who wielded a simple wood log in combat. Like the rest of his group, he was orphaned by the Fire Nation during the Hundred Year War, and though he was not the brightest, his brute strength and remarkable agility made him a valuable addition to the team. While Pipsqueak eventually abandoned the Freedom Fighters, he stayed with his close friend, The Duke, and they continued to travel around the Earth Kingdom.
Pipsqueak was with Jet and the other Freedom Fighters battling a group of Fire Nation soldiers at a camp, where he bent the swords of two Fire Nation soldiers with one mighty swing of his log. When Jet introduced Pipsqueak to Avatar Aang and the others, Aang mistook The Duke for being Pipsqueak, commenting that he had a funny name. The real Pipsqueak towered over Aang and grunted threateningly, questioning the latter on his previous statement, to which the young airbender simply remarked that it was "hilarious". After a pause, Pipsqueak burst out laughing with Aang and The Duke following his example and gave Aang a friendly slap on the back, which inadvertently knocked the Avatar flat on the ground. After snooping through the camp's supplies, The Duke and Pipsqueak found barrels full of blasting jelly and boxes with jelly candy. The Freedom Fighters loaded up their loot in a cart that was pulled back to the hideout by Pipsqueak.
Pipsqueak was part of Jet's small team that harassed an old Fire Nation civilian strolling through the woods; by pinning the elder to the ground, Pipsqueak gave Smellerbee the opportunity to rob the man of his possessions.
Later, when Jet was explaining the plan to flood Gaipan to the rest of his Freedom Fighters, Pipsqueak caught Sokka spying on them from the shrubbery and pulled him out of his hiding place by his warrior's wolf tail. He was subsequently ordered, together with Smellerbee, to take Sokka for a long walk to prevent him from warning Aang and Katara about their plans for Gaipan. During the walk, Sokka berated them for supporting Jet's plan, though Pipsqueak countered by saying that things always worked out under Jet's leadership. When Sokka suddenly fled, the large warrior and Smellerbee gave chase, though each stepped on a Fire Nation trap hidden under some leaves and lychee nuts, which suspended them high up in the trees. After Sokka mocked their knot tying skills and ran off, Pipsqueak, squeezed inside the small cage, casually asked his female companion if she was going to eat her lychee nuts, to which she replied by throwing one against his head; unfazed, he enthusiastically picked it up to eat it.
Despite their open admiration for Jet, both Pipsqueak and The Duke lost all faith in their leader after his plan to destroy Gaipan with a flood. The plan was foiled by Aang, Katara, and Sokka, and soon after, Pipsqueak and The Duke parted ways with the Freedom Fighters and traveled through the Earth Kingdom, foraging and stealing for food and struggling to survive. The two eventually came across Hakoda's ship one night and attempted to raid it, but were caught in the act and captured. After hearing their story, Sokka and Katara welcomed Pipsqueak and The Duke to join their makeshift invasion force. During their time at Chameleon Bay, they were described as "surprisingly helpful", when they were not getting into trouble.
Pipsqueak and The Duke arrived with the rest of the invasion force on the Day of Black Sun. As usual, they made an effective fighting force during the battle. However, the invasion failed and the group was forced to surrender, with only the younger members escaping on Appa with Aang's group. The Duke was among those to escape, but Pipsqueak stayed behind, so the two parted ways. Pipsqueak was sent to a prison near the Fire Nation Capital with the rest of the invasion force, excluding Hakoda.