[1] The film received its title from a line from The Godfather Part II directed toward Cazale's character of Fredo Corleone, and acts as a retrospective of Cazale's distinguished acting career, which was cut short at age 42 when he died of lung cancer.

[4] While Streep, Al Pacino, Gene Hackman, Robert De Niro, and directors Francis Ford Coppola and Sidney Lumet all gave interviews, Michael Cimino, who had directed Cazale in The Deer Hunter refused to participate at any capacity, despite his compassion and respect for the actor.

Victoria Large wrote that "while I Knew it Was You works as a wonderful career retrospective for fans or a great primer for newcomers, the real power of the piece lies in the juxtaposition of the highlights of Cazale's career with the warm remembrances of his friends and the biographical facts of his life.

"[4] Don R. Lewis of Film Threat felt that the film did not properly cover Cazale's early life, writing, "From its awkward running time of 40 minutes to the way director Richard Shepard completely skims over the man's life outside of acting, I just didn't feel there was enough going on to make this doc truly special.

That being said, I Knew It Was You is an excellent tribute piece to a fine actor and a great way to learn more about the roles and work ethic of Cazale.