Martin Sheen originally suggested Michael Douglas or Mel Gibson for the lead role, but Emilio Estevez had written the main character's role specifically for his father and refused to make the film if Martin Sheen did not take part in it. During a screening of the film, Estevez turned to Sheen and said jokingly, "When Michael Douglas sees this, he'll fire his agent."
When one takes the 500 mile Camino de Santiago, they carry a scalloped shell with them as an identity. Emilio Estevez was given such a shell by a man who made that journey six times. When he made the journey while filming the film, he kept the shell with him.
Martin Sheen's father and Emilio Estevez's grandfather was a Spanish immigrant from the region of Galicia, where the Santiago Cathedral is located and the procession pictured in the movie ends. According to Sheen and Estevez, the movie explores and is a homage to their Galician heritage.
In an LA radio interview on "The Busted Halo Show with Father Dave", Emilio Estevez revealed that much of the inspiration he got for this film was the identical pilgrimage that his father Martin Sheen and his son Taylor Estevez made a few years before on the Camino de Santiago de Compostela in Spain. Estevez' son, then 19, fell in love, moved to Spain, and got married a few years later. Since that trip, Martin Sheen and Emilio Estevez spoke often of how they could make a film about the pilgrimage until an idea surfaced.