Chrono Trigger was scored primarily by Yasunori Mitsuda, with contributions from veteran Final Fantasy composer Nobuo Uematsu, and one track composed by Noriko Matsueda. A sound programmer at the time, Mitsuda was unhappy with his pay and threatened to leave Square if he could not compose music. Hironobu Sakaguchi suggested he score Chrono Trigger, remarking, "maybe your salary will go up."
Mitsuda composed new music and drew on a personal collection of pieces composed over the previous two years. He reflected, "I wanted to create music that wouldn't fit into any established genre ... music of an imaginary world. The game's director, Masato Kato, was my close friend, and so I'd always talk with him about the setting and the scene before going into writing." Mitsuda slept in his studio several nights, and attributed certain pieces—such as the game's ending theme, To Far Away Times—to inspiring dreams. He later attributed this song to an idea he was developing before Chrono Trigger, reflecting that the tune was made in dedication to "a certain person with whom [he] wanted to share a generation". He also tried to use leitmotifs of the Chrono Trigger main theme to create a sense of consistency in the soundtrack.
Mitsuda wrote each tune to be around two minutes long before repeating, unusual for Square's games at the time. Mitsuda suffered a hard drive crash that lost around forty in-progress tracks. After Mitsuda contracted stomach ulcers, Uematsu joined the project to compose ten pieces and finish the score. Mitsuda returned to watch the ending with the staff before the game's release, crying upon seeing the finished scene.