- Viewtiful Joe- the protagonist of game and a admirer of Captain Blue.
- Silvia- the damsel in distress of the whole game and Joe's girlfriend.
- Alastor- Jadow's elite soldier and Joe's rival.
- Captain Blue
- Fire Leo- a lion who has a warrior apperance and has fire-style attacks thumb|280px|right|Trailer
- Charles III- is an arrogant and snobbish bat-like agent.
- Hulk Davidson - is a rhino-like agent who was responsible for Captain Blue's scar.
- Gran Bruce - is a shark-like agent, who is lower on the intelligence scale than most of the other Jadow members.
- Another Joe - Actually Alastor in disguise. Looks just like Joe, but with a dark pink visor.
While Joe and his girlfriend Silvia are at the theater during a date, Silvia is kidnapped by the movie's antagonist and taken into the world of the movies: Movieland. Joe is able to follow Silvia, after being picked up and taken into Movieland by the robot Six Majin. Inside the movie, Joe must rescue Silvia from the evil Jadow, the game's organization of villains. To help him, Captain Blue entrusts him with a V-Watch, telling Joe to transform into a superhero upon saying "Henshin" (Japanese for 'Transformation'), but Joe made it into his personal catchphrase, "Henshin-a-go-go, baby!"
Viewtiful Joe's gameplay is very unusual, and draws inspiration from classic side-scrolling brawlers such as River City Ransom and Double Dragon. Joe has no blocking moves when fighting; he only can dodge by jumping or ducking. Usually, by successfully jumping or ducking, the foe that attacked him will be dazed, leaving the enemy wide open for attack.
Joe has three 'VFX' (Viewtiful Effects) powers, which are designed to emulate camera tricks seen in movies such as The Matrix:
Slow - causes Joe's attacks to be more powerful, as well as increasing his reflexes and giving him the ability to dodge most attacks. While in Slow, striking a dazed foe sets up all enemies on the screen for a chain reaction, causing all points accrued during the duration of Slow to be multiplied by the number of enemies struck. If used deftly, Slow will accumulate a very large number of points due to the multiplier effect. If Joe is attacked while in Slow, he will automatically do a dodge move, and will lose a large chunk of his remaining VFX power.
Mach Speed - allows Joe to run at incredible speed, create multiple after-images of himself when he unleashes a flurry of attacks, and can cause his attacks to envelop himself in a temporary heat shield, which will render him immune to flame attacks and set enemies on fire when struck. When used in tandem with Slow, Mach Speed only increases Joe's walking speed while in slow. It also allows "rapid" punches to be used, by holding the attack button.
Zoom - gives Joe access to a new group of attacks and will power up his normal attacks, as well as "dazzling" all of the lesser foes in proximity to Joe into paralysis. Joe's punch is replaced with the "Red Hot One Hundred", a flurry of fists (different from Mach Speed). Joe's kick is replaced with an energetic spin kick, where he levitates in the air as he spins repeatedly. Jumping causes Joe to corkscrew into the air, damaging anything in his path. If the player zooms in while in the air, Joe will careen towards the ground feet first and send shockwaves out from the point of impact.
All of these are used in combat, and to solve the game's puzzles. Two of Joe's attack powers can be used at the same time, Slow and Zoom, Mach Speed and Zoom, or Slow and Mach Speed (When using Slow and Mach Speed together, Joe moves at a normal speed while everything else is slowed). The most powerful attack in the game, the "Slow Zoom Red Hot One Hundred" (SlowZ-RHOH), is done by enabling Slow, Zooming, and then punching your enemy. Using Mach Speed while attacking speeds the attack up slightly. All of the VFX powers are required to get past at least one area in the game. Joe has a VFX meter, which empties as he uses his powers. If it runs out, Joe reverts to his normal state until the first bar of the meter refills. In his normal state, Joe takes double damage, has weaker attacks, loses the double jump ability and can no longer use his VFX powers. The bar can be extended by collecting various film cans scattered throughout the stages. For every fifty collected, a small extension a third the length of the initial VFX bar is added, up to five extensions. Picking up small blue juice cans gives a small boost to the VFX bar (and can extend beyond the length of the VFX bar available), large blue bottles fill up a significantly larger portion, and red bottles give infinite VFX power for a limited time.
- Before the battle with Hulk Davidson, Joe is asked "So what's with the V-Watch on your arm? What, you think you're some kinda Mega Man or something?", referring to Capcom's famous little blue robot.
- At the start of the level "Midnight Thunder Boy", Joe talks to his fists, saying "Time to go to work, guys!" This same line is said by Dante at the start of Devil May Cry except that he is talking to his guns, Ebony & Ivory.