Landgraf was born in California to father John R. Landgraf, Ph.D., a pastor, and Barbara Landgraf (née Joslin). When he was very young, his parents traveled constantly, performing as backup Singers for the gospel evangelist Rev. Mel Dibble, who was part of Billy Graham Crusades. When he was 5 years old, his mother completed an M.A. in social work and his father completed his PhD in family counseling. In 1969, when he was seven years old, his parents divorced.

After spending much of his childhood moving, Landgraf spent his high school years in Oakland, California, and graduated from Skyline High in 1980.

In 1984, Landgraf received a B.A. in Anthropology from Pitzer College, one of the Claremont Colleges.

In 1988, Landgraf was Director of Development at Sarabande Productions, where he eventually became Senior Vice President.

From 1994 to 1999, Landgraf was Vice President of Primetime at NBC where he oversaw the development of The West Wing, and other popular TV shows that included Friends and JAG.

In 1997, Landgraf married Actress Ally Walker. They have three sons and live in Santa Monica, California.

In 2004, Landgraf was President of Entertainment of FX Network, responsible for original TV shows that included critically acclaimed shows like The Shield and the Denis Leary-starring show, Rescue Me.

In 2005, Landgraf was promoted to President and General Manager of FX Network, a position that oversees the management FX, FX HD, the Fox Movie Channel and FX Prods. In this position Landgraf is responsible for the operations, programming, development, scheduling, and marketing of the TV channels he oversees.

Since taking over his leadership role at FX, the number of original programs has increased exponentially. During the 2015 Television Critics Association presentations, Landgraf expressed concern that while television is undergoing a golden age, there is simply too much television.