The player can only control one character at a time. The other party members' activities are governed by a system called the 'Paradigm Shift'. Paradigms are described as 'stances' or 'classes' the characters temporarily take during battle to specify the skills they use. They're more strict than job classes; for example, the party member with a Medic's role can do nothing but heal, while the Commando's role forces them to only attack with non-elemental attacks.
The gameplay makes use of the Command Synergy Battle system, a more fast-paced menu based battle system which derives from the Active Time Battle system. The player controls the party leader, and chains as many activities as there are ATB gauges, with different actions consuming different amounts of ATB. The party's abilities and actions are dependent on the current paradigm, with battle requiring the player to change between paradigms and to level the paradigm functions via the Crystarium system. The first half of this game is linear, while the latter half opens up once the party reaches Gran Pulse.
The system opens up in phases, and party members can't develop further after reaching the end of the current phase. The last stage of the Crystarium opens by beating the final boss, meaning to fully develop the celebration players should take on the post-game content.
The game's progression is chapter-based, and in most chapters, the participant will see the story through different characters' view. Players can move around the area map whilst controlling the party leader, the other members moving independently, sometimes running ahead, engaging in dialogue, or stopping to examine items on the field and pointing matters of interest out to the party leader. Other party members being far away from the leader does not affect their participation in battles that take place in another module. Players can jump, but only at specific jump spots marked on the map.
Characters increase in power in a system like the Sphere Grid from Final Fantasy X called the Crystarium system. Characters win 'Crystogen Points' in battle, and can use them to purchase stat boosts, spells and other skills on a circular graph. The skills a character learns affects their ability to learn other skills and opens new paths on the graph--learning Fire, for example, opens a skill path that leads to Fira and other spells.