Within an hierarchy, only a select few have the traits to make it to the top. And the position is usually an prestigious one, but it isn't exactly an easy one; since the leader is normally held responsible for the actions of their subordinates. But in exchange for their added responsibilities, they get all the fame and riches because they're the reason why things are running efficiently.
There's also times when an character wants to be in charge because they actually hate their current leader. This can range from being mistreated at the hands of their superior to just having issues with their self-esteem. Of course, this can also generate a few false positives if the current leader is paranoid enough to assume that their subordinates wants to usurp them.
And this trope also comes into play when a character appoints themself as the leader and nobody recognizes this; resulting in the new general being quite an nuisance or ruining everything with their inexperience.
When this happens out-of-universe (meaning, when the author and/or the studio promote a character as being the leader when in the work itself the leader is someone else), it's Informed Leadership.
Anime & Manga
- Sailor Mars became this in the DiC dub of the first Sailor Moon anime. Rei Hino had her issues with Usagi and the two did bicker a lot in the first season, but she knew her role and stuck to it. DiC's Raye, on the other hand, demanded to be made leader of the Sailor Scouts at least twice, tried to kick Serena out, and stole the Moon Wand from her at one point. (In the original, Usagi had given it to Rei for safekeeping.) This is notably absent from the original manga, where Sailor Venus is the leader; Rei butts heads with her from time to time, but never tries to usurp Venus's position.
- Joe the Condor had shades of this in Science Ninja Team Gatchaman, but like the Sailor Moon example above, his Battle of the Planets counterpart Jason was much worse.
- Danny fancies himself the leader of Ocean's Eleven (to the point that the team is named after him), but most of the team follows Rusty's lead.
- Buffy tries to act as the leader of the Scoobies, but her Hair-Trigger Temper and Jerk with a Heart of Gold tendencies mean few in her team usually follow her lead, and often question her authority.
- Ludwig in Mario & Luigi: Paper Jam considers himself to be the leader of the Koopalings, but at least four of them never agreed on appointing one.
- The website is named after Homestar Runner, but Strong Bad fancies himself the main character on the site due to being the Ensemble Darkhorse. This cartoon lampshades it by having Homestar allow Strong Bad his "weekly power play."
- Whenever Numbuh One of Codename: Kids Next Door is absent for at least a few hours, Numbuh Four is quick to assume command. But due to his role in the team, he usually does an terrible job as the leader or someone else takes over.
- Aang is supposed to be the leader of Team Avatar (hence why they named the team after him), but he's peaceful and kind and not the bossy type, so Katara tends to take the reins. He's fine with that, though Katara takes issue when Sokka insists he should be the leader.
- Peridot tends to pass herself as Leader of the Crystal Gems in Steven Universe.
- While no one questions Shiro as the leader in Voltron: Legendary Defender, he wanted Keith to take his place if anything happened to him. Sure enough, he disappears, and when Keith tells the team what Shiro said Lance throws a fit, yelling that he doesn't want Keith leading him anywhere and getting pouty when the Black Lion rejects him. He gets over it quicker than most examples when Black does indeed choose Keith, though, and accepts his role as Keith's Lancer.