The 37-year-old "Passengers" star's father died after a long battle with multiple sclerosis.
Pratt, who found out of his father's passing while filming Jurassic World, says it wasn't until he began filming Guardians of the Galaxy: Vol. 2 that he forced himself to fully digest his feelings.
"The truth is I ripped open some wounds that had been healing for some time," Pratt said in an interview with British GQ.
"And I didn't want to. But I knew it was right for the moment...There are wounds that are never going to be totally healed.