The music video for "Part of Me" was directed by Ben Mohr, filming began on February 16, 2012, and took place over the course of three days at the USMC's Marine Corps Base Camp Pendleton in Oceanside, California. After a couple of days of the song's release, Perry confirmed via Twitter that she was shooting a video for the song tweeting: "Holy power of the Grammy's, Part Of Me is already top 10 on iTunes! U guys are killing it! NICE! Can't wait to shoot this video! #grateful." Perry later revealed that before filming began she had to undertake vigourous training, learning such things as rope climbing, Military etiquette, combat training, and more. As filming began to take place, pictures from the set of the video surfaced online, the pictures showed Perry with short hair and dressed in Military clothing. On March 16, 2012 Capitol Records released an official trailer for the video, the video shows different clips of Perry doing various Marine related routines and ends with the announcement for the video's official release date of March 21, 2012. The music video premiered on March 21, 2012 during the program MTV First: Katy Perry. During the program perry revealed her experiences filming the video and the inspiration for the plot stating:
"Well, I actually had the idea, I wrote the story about what it is actually like to be in the Service, and it does take a lot of physical strength, but now that I've been through it - and even just for the three days I was there, [it's] a lot of mental strength. We used only marines, no actors or actresses. We used all of the marine's equipment and they were so lovely to us, I always have fun even though it's a lot of work. Even though I was sore and exhausted, I was so educated on people in the service, who I've always respected but the stuff they go through, and the kind of loyalty they posses, it's very communal, and community. Not to sound weird, but it seems like the heart of America. Seriously, the heart".
As Perry sits in her car gazing at her necklace, she notices her boyfriend cheating on her. She confronts him in his office and they break up. As the titular track begins; she drives to a gas station and buys a can of tea inside the shop. After paying for her items she notices a moto-sticker on the bulletin board; the sticker reads "All women are created equal, then some become Marines". Increasingly emotional, Perry gathers her possessions and enters a nearby restroom to begin to change her identity. She cuts her hair and changes into a hoodie and jeans. Perry enlists in the United States Marine Corps and, after a brief scene in recruit training, she reports to the School of Infantry for the Marine Corps' rigorous basic combat instruction course. Perry eventually finds herself reminiscing over her experiences with her ex-boyfriend, yet remains spiteful towards him, burning a love note next to a LAV-25 and venting frustration through MCMAP, the Marine Corps Martial Arts Program. Throughout the remainder of the video Perry is shown in training as well as dancing beneath a large garrison flag. The video ends with Perry's final transformation into a basically trained warrior, clad in MARPAT camouflage utilities, body armor and camouflage face paint.
The video garnered positive reviews from critics with many praising its girl power theme and Perry's different approach in comparisons to her previous music videos. Ethan Sacks from New York Daily News said "[The singer] dons combat fatigues and aims some barbed lyrics, perhaps at Russell Brand [...] Katy Perry has traded her whipped cream-spewing brassiere for USMC issue MARPAT for her new video. Judging by the way Perry handles a bayonet in the "Part of Me" video, Brand may want to consider staying half a planet away." Bruno Nessif from E! Online wrote "After channeling some Demi Moore in G.I. Jane and chopping off her hair, Perry enlists and trades in her handbag and cell phone for some MARPAT fatigues and combat boots." Ray Rahman from Entertainment Weekly gave the video a positive review: "It’s less G.I. Jane and more In the Marine Corps Now, but Katy Perry’s new pop-military video for “Part of Me” is still an intense ride." Jenna Busch gave the video a positive review, commending it's girl power, writing "Instead of showing traditional break up visuals like burning some guys clothes, fights with no sound, punching walls, etc., "Part of Me" has Perry joining the United States Marines. It's actually far more dramatic to see her, post break up, hacking off her hair in a bathroom than it would be to see her crying in the rain or something." Wendy Geller from Yahoo! Music gave a positive review of the video stating: "Perry, arguably one of the girliest girls in entertainment these days, puts up a surprisingly convincing hard front as she shoots a gun, wrestles soldiers, crawls under barbed wire, and scrambles up ropes. The video ends with a striking closeup of Perry, makeup-free except for camouflage face paint, staring down the camera. It's a remarkable way to make her point that no ex will ever break her spirit or her strength--and, it's sure to be a hit with the girl-power set this year."
James Montgomery from MTV praised the video and Perry's role saying: "Over the years, Perry has been a California Gurl, a nerdy teenager, an alien and just about everything in between, but up until now, she's never really been an actual person." He went on to praise the video stating: "Part of Me" is unlike any pop video in recent memory. Rihanna did military chic in her Hard video (she even straddled a tank), and just about every one of Perry's pop contemporaries have ventured down the same path. But they were never really in the military; they were just making it more fabulous. Perry takes the opposite tact: She cuts off her hair, she eschews makeup, she fights, crawls, suffers. It's a commendable level of commitment. Your move, everybody else."  Amelia Proud from Mail Online also made note of Perry's new image in the video and comparisons to o Rihanna stating: "She is known for her long dark locks which she occasionally mixes up by donning bubblegum-pink or bright blue hues. But in her latest video to accompany her new single Part of Me Katy Perry is seen furiously hacking off her hair. The 27-year-old transforms her luscious tresses into a messy boyish crop, which makes her look dramatically different from her usual girlie appearance. The video, which has a starkly aggressive tone, tells the story of a small town girl who gets her heart broken and channels her pain into tough physical training in the military. But it appears that Katy may well have taken inspiration from one of Rihanna's old videos."
While the film earned positive reception for it's encouragement of "girl power", feminist author Naomi Wolf criticized the video and accused it of being propaganda for the Marine Corps. Wolf released a statement via her Facebook page saying: “I really want to find out if she was paid by them for making it . . . it is truly shameful. I would suggest a boycott of this singer whom I really liked if you are as offended at this glorification of violence as I am.” Glenn Seilg, founder of The Publicity Agnecy responded to the claims on Fox News Live stating: “In her efforts to boycott the video, Naomi Wolf has brought more attention to it, without her comments, most people would clearly have seen the military simply as a metaphor and not as an attempt by Katy Perry to glamorize the military or war. Perry told MTV that she chose the military plot because it represented the song, saying, "It's an affirmation of strength, so I wanted to go the strongest route I ever could."