Frank only has a brief role in the first movie, where he is working at a locksmith stand in New York, and provides information to K about the Arquillian galaxy. When J meets him, he mistakes the owner of the locksmith stand as being Kay's source and proceeds to state he was definitely an alien and had the worst disguise ever, with Frank then replying that J can "kiss [Frank's] furry little butt" due to thinking J was talking to him, to Jay's shock. He was planning on leaving Earth due to Edgar the Bug's impending invasion, which he tried to tell Kay how he didn't have time to talk.
Kay grabbed him and begins shaking him roughly, loudly declaring that they've got a stray with the implied threat that Frank will be sent to the pound if he didn't talk. Frank divulges that the galaxy is a source of unimaginable power, hence why the Bugs were after it. He also reveals that the Galaxy was around the size of a marble, which is why and how it can be on Earth. He then departs, although not before barking at a cat causing Jay to realize what the Arquillian's last words about the galaxy being on Orion's Belt meant.
Frank has a larger role in the second movie and becomes Jay's partner, but proves only to be a nuisance, terrorizing other MIB personnel (including attempting to "neuter" one of them for laughing at him), and joking around during missions. He mentions that he worked in the MiB mailroom before being Jay's partner. He accompanied Jay to bring Kay back and later becomes an assistant to Zed, which he accepted largely due to the dental plan. When Serleena took over MIB headquarters, Frank stayed out of reach and in touch with Jay until Serleena discovered and captured Frank after her fight against Zed. It is possible that he was freed by the Worm Guys when they, Kay and Jay fight to get back MIB Headquarters from Serleena as he is later seen drinking and smoking with the Worm Guys and contacted by Jay when he, Kay and Laura are fleeing from Serleena and mistakenly thinks Jay to have been shot down and killed by Serleena when she fires at the MIB car disabling connection between Jay and Frank. Later on, he with Kay and Zed attempt to cheer Jay up from the departure of Laura back to Zartha, only to end up causing disgust to everyone when he starts shaking himself, and is shocked that the human universe is itself a locker within an immense alien train station
In the MIB series it is revealed that the "human" at Frank's newspaper stand is merely a robot, and also that Frank's true alien form still resembles a pug, albeit with a dark green color, antennae, and a 3-pointed tail. Sometimes he gets into trouble such as swallowing a core that acts like a small black hole, getting his body possessed by a small alien, getting boiled alive by Drek, and having to help Kay and Jay against alien terrorists and bad worms.
Frank did not appear in person in the threequel, but can be seen in a picture in J's room as well as on a Coney Island billboard as "The Incredible Speaking Pug". Barry Sonnenfeld has revealed Frank was excluded so they do not continually rely on the same characters (which also explains the absence of Jeebs and Zed) and that the Coney Island talking dog, is in fact the "secret backstory" of Frank. Frank the pug is featured on the cover art for MIB: Alien Crisis as well as the main story, and appears in the Men in Black III App game as Agent F and serves as the player's partner.
Frank the Pug is featured as a main character, and on the cover art for the video game Men In Black: Alien Crisis. With J and K missing, Frank is working with Agent C - who has recently moved into fieldwork from administration to prove herself- and new MiB recuit Agent P - an art thief who was hired by the Adorian war criminal Emilo Chauncy and was recruited after he showed exceptional skill in dealing with an alien ambush- to prevent Earth being caught up in a civil war. Frank was present with P (who was formerly known as Peter Delacour) when they were flying a car to the MiB headquarters and pursued by Adorians while C pursued an escaping Chauncy. After arriving at the base, Agent C and Frank interrogated Peter about the book, to which Peter told he had no idea what Chauncy wanted with the book. Frank eventually met with C and Agent O, who scolded C for failing to arrest Chauncy. During the conversation, Frank noticed Delacour slip out of the room and alerted C and O. Frank later witnessed the neuralyzing of Delacour into Agent P.
Frank appears in as a cameo in the spin-off. By 2019 he has retired and settles with a new guard. When a unknown person enters the building he ask the the guard if he is going to call it in.
- There is a website FrankThePug.com which provides extensive information on pug breeding.
- Frank appeared in Air New Zealand's Safety Video, along with Zed (Rip Torn).
- Frank was played by the dog Mushu. Mushu passed away not too long ago, and was not replaced by another dog in Men in Black III.
- Men in Black
- Men in Black: The Series
- Men in Black II
- Black Suits Comin' (Nod Ya Head)
- Men in Black III (Picture only)
- Men in Black: Alien Crisis
- Men in Black International