For years, Zack Bradley (Dane Cook) has toiled away as a box-boy at the local Super Club, sharing his living space with his grandmother. During his downtime, he enjoys hanging out with his co-workers, including the quirky Lon Neilson (Andy Dick), the wise Iqbal Raji (Brian George), and the eccentric Russell Porpis-Gunders (Harland Williams). Although Zack often embodies the quintessential "slacker," he possesses a benevolent heart, earning him popularity among his peers. The reigning king of the workplace, Vince Downey (Dax Shepard), claims the title of Employee of the Month for the 17th consecutive time. Vince is not only arrogant but often degrades his co-workers, particularly Jorge Mecico (Efren Ramirez), whom he relentlessly belittles.
The dynamics shift dramatically when Amy Renfro (Jessica Simpson) steps in as the new cashier. Both Zack and Vince quickly find themselves enamored by her, igniting a fierce rivalry as they vie for her affections. Although Amy goes out to dinner with Vince, she finds him utterly repulsive, yet Vince remains oblivious to her discomfort, convinced they shared an enjoyable kiss.
Upon learning that Amy previously dated the "Employee of the Month" at her former job, Zack resolves to claim that title for himself. Motivated to impress Amy, he transforms into a more dedicated worker, posing a serious challenge to Vince. A moment of connection occurs when Zack manages to take Amy on a date—entirely at the Super Club—much to Vince's chagrin.
As the days roll on, Zack soon realizes that attaining the title of Employee of the Month is far more challenging than he anticipated. With Iqbal cheering him on, Zack finally finds his rhythm, much to the dismay of Vince, who's fixated on retaining his title. A game of sabotage ensues, with Vince attempting to undermine Zack’s progress, even breaking into his house to manipulate the clocks, but Zack manages to thwart these plans.
Zack’s commitment gradually leads him to a significant dilemma: when he agrees to take Iqbal's shift on a crucial championship slow-pitch game day against the rival chain, Maxi-Mart, he inadvertently jeopardizes Iqbal's job. His friends express their disappointment, believing Zack is beginning to mirror Vince’s selfish ways, especially since they suspect his motives are primarily driven by his desire to win over Amy. Overhearing their conversation, Amy reveals her disdain for Zack, revealing that her prior beau, a former Employee of the Month, was just as selfish and disrespectful.
As the month comes to a close, a tie emerges between Zack and Vince. On the day set for a decisive showdown, Zack contemplates quitting, instead deciding to redeem himself by getting Iqbal reinstated. He takes a moment to sincerely apologize to Lon, Iqbal, and Russell, committing to pursue the title not for recognition but for his own pride. Just when it appears Zack might back out, his friends rally around him, claiming he never submitted his resignation after all—backed by a bribery scheme involving a broken Butterfinger.
Eventually, the contest for the fastest checkout proceeds, and in a surprising twist, Vince narrowly secures victory. However, the tide turns when Semi (Marcello Thedford), the store's security guard, unveils footage that reveals Vince's dishonesty during the competition. Faced with undeniable evidence of his dishonest practices, Vince is terminated and required to wear a tracking device due to the legal ramifications of his actions.
In the end, Zack triumphs, not only earning the title of Employee of the Month but also fostering a budding romance with Amy. Six weeks later, with Vince now on probation at a competing store, Jorge finally musters the courage to confront his former tormentor, treating Vince with the same disdain he once endured, albeit with the kindness of offering him a ride to the bus stop, keeping Vince's probation status in mind.
