Flapjack is the main protagonist of the series, The Marvelous Misadventures of Flapjack. He is a young boy from Stormalong Harbor who dreams of becoming a great adventurer. He hopes that with the help of his best friend, Captain K'nuckles, his dream will come true, while being oblivious to K'nuckles' incompetence.
Flapjack has curly, blond hair, along with blue eyes. He wears a light olive drab scarf, a white & red striped t-shirt, and blue pants. He also sports a white sailors cap.
Flapjack is very naïve and oblivious to danger, thus he is easily caught up in perilous situations. He is a strange, cute, and funny little boy. Flapjack is a quirky, kind, and energetic young boy who greatly wants to be a strong adn fierce adventurer. He is a gullible and naïve boy who will easily be taken adventage of due to his kindness and purity.
When Flapjack was just an infant, Bubbie supposedly found him out in the sea, in a floating bundle of seaweed. When she took a closer look at the child, she declared him as her "little angel". A man in a boat making flapjacks then passes by, baby Flapjack likes the name and Bubbie decides to name him "Flapjack." From then on, Bubbie decided to raise Flapjack as her own, taking him with her to Stormalong Harbor.
Sometime later, a now older Flapjack and Bubbie were out at sea when they discovered a drowning K'nuckles. After saving the old sea captain, he began telling various tales of his adventures from before he got lost. When K'nuckles told Flapjack of Candied Island, Flapjack became very enthusiastic, and decided to become an adventurer like K'nuckles. He has stuck by K'nuckles side ever since.
- According to Thurop Van Orman (Flapjack's voice actor), Flapjack is 7 years old.
- According to the episode K'nuckles is a Filthy Rat, Flapjack's blood carries a natural immunity (antibody) to the Bubonic Plague.
- He wears purple underwear, as revealed in the episode "Jar She Blows", however, occasionally wears white underwear.
- Flapjack has a knack for writing original lyrics and melodies for songs, and has a "beautiful singing voice," at best. His songs have included a lullaby for K'nuckles, a friendship-themed song involving K'nuckles, a musical tribute to a little old lady, and about 366 more unknown songs.
- In the episode "That's a Wrap", K'nuckles stated that pants are for sissies. Flapjack (cluelessly) agreed, yet Flapjack wears pants in every episode so far.
- Flapjack was originally going to be voiced by actor/comedian Paul Reubens, but Reubens was unable to voice him at the time, so Thurop Van Orman decided to voice Flapjack himself.
- Flapjack is K'nuckles' "Guardian Angel" in "My Guardian Angel is Killing Me!".
- Flapjack is a playable character in Cartoon Network's game, TKO. One of Flapjack's moves is called, "Hey, Bubbie" and when used, Flapjack launches Bubbie at the enemy. Peculiarly, Bubbie is very small in comparison to Flapjack.
- Flapjack's first word was his own name.
- Flapjack has been shown to have been a sailor multiple times in the series. In "N is for Navy" he was said to have been their best recruit. In "All Hands on Deck" he pretended to be a sailor in order to impress the "real" sailors.
- Flapjack was kidnapped by a sailor crew in "These Boots Were Made for Walking (On Your Face)", but instead of blaming K'nuckles, Bubbie decides to form a plan to get him back.
- Flapjack has made a cameo in Snafu's webcomic, PowerPuff Girls Doujinshi. He is seen shielding his head and running away from Buttercup during Dojo class.
- Thurop Van Orman, who plays Flapjack, also voices Lil' Gideon in Gravity Falls.
- Flapjack bears a virtual resemblance to Boomer of the Rowdyruff Boys from The Powerpuff Girls. The two have swooped-up blonde hair, blue eyes, are very naïve/immature, usually being taken for granted.
- Flapjack is briefly mentioned at the end of the Steven Universe episode "Say Uncle."