Youthful rulers are common in literature and history. If children, they are depicted as adorable; if in their teens or twenties, they simply create a sense of awe and protectiveness in their older advisers. Their naive simplicity may in fact make them good (and sometimes ruthless) rulers, as they prefer to cut through the red tape of court etiquette.
Because of their youth and inexperience, they are often underestimated by the villains, who are frequently Evil Uncles/Chancellors/Princes who were responsible for the assassination of the previous ruler, are currently in control, and do not intend to give it up. If the Queen Mother is regent, she is likely to over-control the young monarch and be unwilling to put down her power, though she is less likely to be actively evil.
They usually exhibit great wisdom in the course of the story, thus justifying their enormous power despite their youth. They may have friends (or adventures) among the servants or guards, giving them an insight into the lives of their subjects that their stuffy courtiers would scorn. They may have to resort to King Incognito to get anything done. Rebellious Princesses sometimes become good examples of this trope.
The Trope Namer is a line from The Bible, specifically Isaiah 11:6 ("...and a little child shall lead them.").note
Compare Royal Brat and Young Conqueror. The Wrongful Heir to the Throne or the Evil Chancellor etc. may actively try to encourage this, and the young ruler must shake them off. The corporate version of this is the Grade-School C.E.O., the petty leader Young and in Charge. If the entire government is children, not just one ruler, you're looking at a Teenage Wasteland.
- In The Princess Thieves, Queen Victoria flees Britain, leaving her estranged granddaughter, Princess Gwendoline as the heir to the British throne, which is currently held by her regent, the Duart Archduke of Buckingham.
- Jenny Sparks, leader of The Authority, died with the 20th century; her successor, Jenny Quantum, was soon born and adopted by the team's Official Couple. Eight years later, after everything had gone to hell in a handbasket, little Jenny Quantum got sick of watching the adults screw it up: she aged herself to 14, reassembled the team and has led them ever since.
- Prez (1973) depicts Prez Rickard, the first 18-year-old President of the United States. He's Wise Beyond His Years and a staunch opponent of the political machine.
- Prez (2015) features Beth Ross, a teenage girl elected president by Twitter in 2036.
- The Sandman (1989) #54 has a story-within-a-story about Prez Rickard that takes his noble qualities up to eleven. He does a perfect job for eight years, creates a golden age of peace and prosperity, and resists the temptation of Boss Smiley. Then he walks the earth until he dies and moves on.
- Robin (1993): Tim Drake's classmate Danny is brought in against his will to be the new leader of Kobra due to a birthright.
- Wonder Woman Vol 1: In two of the Wonder Girl imaginary tales Diana meets young magical princesses who are the rulers of their own magical lands due to their queen mothers being missing.
- Wreck-It Ralph: Vanellope von Schweetz, the nine-year old Princess, and later President, of Sugar Rush, a racing video game.
- The Climax: The King appears to be about 10. (He was played by Scotty Beckett who was 14 at the time, but looks much younger).
- In The Hitchhiker's Guide to the Galaxy (2005), the leaders of Magrathea are young children.
- Idiocracy: In the future, the Secretary of Energy is in his early teens. Things like this happen when you give out Cabinet positions in a contest, though he didn't seem any worse at his job than anybody else... although when the population at large is composed of idiots, this isn't too difficult.
- Indiana Jones and the Temple of Doom: The Maharaja is about twelve.
- Star Wars: Queen Amidala of Naboo, as shown in The Phantom Menace, who was aged fourteen (and may have been even younger when first elected). In Attack of the Clones, she mentions that she was not the youngest Queen in Naboo's history, showing that this is an enforced trope.
- Louis, the Child King: Louis is just above eleven and must learn how to rule as the King of France admist the Fronde civil wars while his mother, Anne of Austria, served as regent.
- RoboCop 2, very similarly, has a preteen end up in charge of a Nuke ring.
- Tropic Thunder. The heroin ring was run by a little kid, who was as ruthless as you'd expect a leader to be, and far more capable in combat than one would expect.
- Wee Willie Winkie: She isn't a queen or anything, but little Shirley Temple manages to get warring British and Afghan factions to make nice to each other and make a peace, just with the power of her cuteness.
- Sabaton's album Carolus Rex is predominantly about Charles XII of Sweden, in the Real Life examples below.
- Vocaloid's Story of Evil series of songs features Rin as a fourteen-year-old ruling princess. The result is definitely not pretty.
- The Bible provides the page quote, and the Trope Namer is an unrelated but famous passage about the Messiah.
- Judah had several child rulers, such as Joash, crowned at 7, and Josiah, crowned at 8. Ironically, they were more likelt to "do what was right in the eyes of the Lord." Unfortunately, the former went off the rails in his adulthood.
- While David didn't become king until he was 30, he was Israel's champion and General as a teenager. His son Solomon succeeded him as king when he was twelve.
- Arthurian Legend: By most sources, King Arthur was somewhere in the 15-to-18 range when he was crowned High King. The other rulers were not happy.
- The eighth Guru of Sikhism, Guru Har Krishan, inherited the role from his father when he was five and died before his eighth birthday, making him the religion's youngest and shortest-reigning leader. One of his epithets is Bal Guru, "Child Guru."
- Back when gaining the papacy was more about political maneuvering and outright conquest, Count Alberic III of Tusuculum managed to bribe his twelve-year-old son into becoming Pope Benedict IX. Notably, Alberic's two brothers were his immediate predecessors.
- Janus in the Cool Kids Table game Small Magic is destined to find a way to keep the Oni asleep and the world at peace. Maggie and Stege are called upon to protect him during his Journey.
- Welcome to Night Vale gives us Tamika Flynn, twelve when she let an uprising of children out of the feared Night Vale library, killing a librarian (one of the most feared creatures in the town) in the process. Thirteen now, she has been training an army of children with militaristic precision and the hand of her kill hung around her neck, and appears to be taking the reins against Strex-Corp as of "Missing."
- In Cabin Pressure, the king of Lichtenstein turns out to be a Bratty Half-Pint with a tendency to threaten to try Off with His Head! on his schoolmates, despite his long-suffering sister Princess Theresa telling him he can't actually do that.
- In The Gamer's Alliance, Gerard Aurelac becomes the King of Maar Sul in his early teens and comes up with a plan to capture Pronin whose forces are besieging Maar Sul City in the Godslayer era.
- Eberron: Jaela Daran, the 11-year-old head of the Church of the Silver Flame. She started at 6. Note that this is not standard for her position; by all indications, most Keepers of the Flame are called to their task somewhere in their early adulthood, and her predecessor reigned for sixty years. She is specifically the spiritual head of the church; the Council of Cardinals handles the day-to-day business, and Jaela can only offer advice, except in the rare instances where she receives direct orders from the Flame to pass along.
- Elisabetta Barbados, the 13-year-old Holy Sacred Empress of Abel in Anima: Beyond Fantasy. In fact, she's known as the Child Empress.
- Shakespeare's Henry VI (also a historical figure) was crowned king at nine months old after Henry V died. This is an instance of a child king being portrayed as wholly negative, as he is too young and unknowledgeable to keep his courtiers from the petty in-fighting. Because he has no father to guide him, Henry stays weak and naive, which eventually leads to the War of the Roses.
"Henry VI, in infant bands crowned King/Of France and England, did this king succeed/Whose state so many had the managing/That he lost France, and made his England bleed." (epilogue, Henry V)
- Antony and Cleopatra: Octavius Caesar, though older than most examples, is noted in play by various characters for only being in his twenties and ruling Rome.
- Westeros: An American Musical: Robb Stark, the King of the North, is explicitly stated to be technically fifteen when made King and to have turned sixteen in the Act II song focusing on him.
- OverSimplified: The Han dynasty of China was led by child emperor after child emperor and The Holy Roman Empire had a number as well. Their complete inexperience and inability to rule led them to be easily manipulated by others hungry for more power.
- Arthur, King of Time and Space: Arthur in the "classic" and "space" arcs becomes king in his teens as in the myths, but the modern arc abides by modern law and he isn't informed that he owns controlling shares in Excalicorp until he turns 18 and he doesn't run for POTUS until years later.