Husband and wife developers Tetsuya Takahashi and Soraya Saga originally pitched the concept of Xenogears as a potential scenario for what would be Final Fantasy VII (1997) but their superiors at Square deemed it too dark and complex for a fantasy story. It was also pitched as a potential sequel to Chrono Trigger (1995) but further complications drove the developers to create it as an original concept.
There were concerns early on that the game may not be released in the U.S. due to the overt religious themes and mentions in the story. Further, according to translator, Richard Honeywood, translating the game was a particularly difficult task and he came into contact with it because its previously assigned translators quit or asked for reassignment due to its challenge.
An unused FMV can be found within the data of the game's second disc. The FMV features a song entitled "Stars of Tears", a vocal track performed by Joanne Hogg and composed by Yasunori Mitsuda that doesn't play anywhere else during the game.
There is a poster of Tifa from Final Fantasy VII inside a house in Class 2 Citizen Sector in Solaris.
Lucca from the game Chrono Trigger makes a cameo appearance in the village of Lahan.