Former Division I collegiate wrestler Scott Voss is a 42-year-old bored and disillusioned biology teacher at the failing Wilkinson High School. Budget cutbacks at the school jeopardize the continuation of its music program, which would result in its teacher, Marty Streb, being laid off. Concerned for both his colleague and his students, Scott attempts to raise the $48,000 necessary to keep the music program alive. He moonlights as a night instructor for an adult citizenship class, where student Niko asks him for outside tutoring. When Scott arrives at Niko's apartment, he learns that Niko was a former mixed martial arts (MMA) fighter. While watching the UFC at Niko's apartment, Scott learns that the loser of a fight receives $10,000, which gives him the idea of raising the money by fighting and losing in MMA. Scott, helped by Niko and Marty, begins with small unsanctioned bouts paying only $750 to the loser. Niko begins training him in defense, later adding trainer Mark to teach offense, after Scott knocks out an opponent and realizes that wins give larger payouts, needing fewer fights to achieve his $48,000 goal. While Mark trains with Scott, Malia De La Cruz, one of Scott's students and a band member, helps Niko study for his citizenship test by putting the information into songs. Scott then begins fighting in small MMA fights and gradually gaining higher amounts of money for the school.
Scott has been pursuing the school nurse, Bella Flores, and they share moments revealing affection for each other, while also rekindling Scott's passion for teaching. He begins to engage the class and earns the respect of his students. Scott is within $6,000 of his goal, when Mark tells him that Niko turned down a sanctioned UFC fight offered by Joe Rogan, with the certainty of earning $10,000 for a loss. Scott confronts Niko, who apologizes and admits he turned it down because he was jealous – Niko was once asked to fight at the UFC but suffered a neck injury while training for it, ending his career. Scott and Niko accept the offer, with Scott and his crew soon travelling to the MGM Grand Las Vegas for the fight. Once he arrives, he learns that school administrator Elkins has been embezzling from the winnings and the school, meaning all Scott's efforts have been in vain. Scott decides he must win the fight and the $50,000 purse.
The publicity of Scott's slow rise to fame has grown, and the school's band appears in the stands to play his theme song, thanks to Bella contacting Rogan. During the fight, Marty reminds the losing Scott that even if he does not win, he has inspired the students, which is their real purpose as teachers. Scott has no answer to his dangerous opponent, Ken Dietrich, who is angered that his original opponent cancelled and that he is stuck with a man that "does not deserve" to be fighting at the UFC. After finding inspiration from the students, Scott manages to win the fight, earning $50,000 and Dietrich's respect. Scott and Bella kiss through the chain link fence of the ring.
A subplot involves student Malia, her father, and Scott's brother Eric, who is unhappily self-employed as a house painter. Eric has a large family and both he and his wife have low paying jobs; Eric enjoys cooking. Malia's father has a restaurant that is failing since his chef quit. Malia's father wants her to stop music and focus less on school so that she can help with the restaurant, but she has a passion for music. Scott encourages Malia to pursue her musical talent, which drives hostility from her father to Scott for "telling his daughter to disobey him". Eric becomes the chef for her father's restaurant, which improves the business, so Malia's father is thankful to Scott. Once Malia sings Scott's theme song at the UFC fight, shown on TV, her father tearfully accepts that music is her true passion.
In the closing scene, Niko and all of the students in Scott's citizenship class attend their American citizenship ceremony.
Filming began on March 28, 2011, in and around the Boston, Massachusetts, area. Filming continued on through May 25, 2011, in Lowell and Quincy, Massachusetts, where it wrapped shortly there after, by early June 2011.
Here Comes the Boom received mixed to negative reviews from critics. On Rotten Tomatoes, the film holds a rating of 38%, based on 92 reviews, with an average rating of 4.9/10. The site's consensus reads, "Here Comes the Boom benefits from Kevin James's genial presence, but the film doesn't deliver enough laughs to live up to its title – or enough satisfying plot to make up the difference." On Metacritic the film has a score of 40 out of 100, based on 26 critics, indicating "mixed or average reviews". In its opening weekend, the movie earned $11.8 million in the domestic box office and ended its box office run with $73 million worldwide as a box office success. Here Comes the Boom was chosen as one of ten best films for family audiences by the 21st Annual Movieguide Awards on February 15, 2013."Holly Holy" – versions by Neil Diamond and Charice are heard in the film
"Bouncing off the Ceiling (Upside Down)" by A-Teens
"Joker & the Thief" by Wolfmother
"Optimus Bellum Domitor" by Sak, Williams and Welch
"Boom" by P.O.D.
"Spank" by Jimmy "Bo" Horne
"James Brown Is Dead" by L.A. Style
"New Noise" by Refused
"Holly Holy" by Neil Diamond
"Faithfully" by Journey
"Holly Holy (NSFW Remix)" by Neil Diamond ft. UltraLove
"Pictures" by Joseph Anderson
"I Stand Alone" by Godsmack
"Doin' It Right (Delta Mix)" by Steve Azar
DVD was released in Region 1 in the United States on February 5, 2013, and also Region 2 in the United Kingdom on 18 March 2013, it was distributed by Sony Pictures Home Entertainment.