Meowth's background starts with abandonment as a kitten at Camp Pokéhearst, facing starvation and mistreatment. His earliest memories are of loneliness and scraping for food, actions that led to punishment like when he disrupted activities by tipping over a basket of baseballs. This isolation drove him to seek a better life in Hollywood after seeing a film depicting luxury.

In Hollywood, he joined a street gang of Meowth led by a Persian, surviving by stealing food and causing trouble. He met a female Meowth named Meowzie, who rejected him for being a "street Meowth." Determined to win her affection, he taught himself to walk upright and speak human language through grueling effort. He learned by eavesdropping on language classes, practicing tongue twisters, and later teaching himself to read using a picture book; his first understood word was "rocket." Despite this transformation, Meowzie rejected him again, calling him a "freak," leading to heartbreak and his decision to join Team Rocket.

Initially serving Giovanni directly at headquarters, Meowth was reassigned to Jessie and James after an incident involving spilled coffee and an electric shock. He claims to have been Giovanni's "Top Cat," a status contradicted by Giovanni's actual Persian, whom Meowth resents as a rival. The trio encountered Ash Ketchum and Pikachu in Viridian City, where their first theft attempt failed, igniting their ongoing quest to capture Pikachu for Giovanni's approval.

Meowth acts as the trio's strategist, inventor, and translator. He builds their machines and contraptions, interprets other Pokémon's speech, and devises theft plans. Though he views himself as the group's leader, Jessie and James often ignore his authority. His ability to speak and walk upright cost him typical Meowth battle skills; he never learned Pay Day and is generally ineffective in combat, though he occasionally wins through cunning or cheating, like defeating Brock's Onix by exploiting its water weakness.

Personality-wise, Meowth remains loyal to Jessie and James despite frequent bickering. He exhibits vulnerability, privately reflecting on his past or gazing at the moon contemplating his choices. He shows empathy for abandoned or mistreated Pokémon, relating to their experiences. While presenting as conniving and self-assured, he is easily hurt and craves validation, especially from Giovanni. His romantic pursuits extend beyond Meowzie to others like May's Skitty and a Glameow, though these attractions remain unreciprocated.

Meowth's relationship with Pikachu is complex. He acknowledges they could be friends under different circumstances, and they have cooperated when stranded or in danger, such as working together for survival on an island. Despite this, Meowth stays committed to capturing Pikachu for Team Rocket.

Throughout various regions, Meowth experienced temporary separations from Jessie and James, including a stint in Unova where he infiltrated Ash's group by falsely claiming expulsion from Team Rocket. This ploy failed, leading to his reunion with his partners. His loyalty to them ultimately surpasses his devotion to Team Rocket, choosing to stay with Jessie and James even when the organization's goals diverge.

Meowth has never evolved, partly due to his inability to master Pay Day and his disdain for Persian, his evolved form. He remains a wild Pokémon, avoiding capture in Poké Balls despite occasional interest in Luxury Balls. His character emphasizes resilience amid repeated failures and a persistent search for belonging.