Humphreys was born in the small town of Independence, Mississippi. In 1993, when he was eight years old, he attended an open casting call in Memphis, Tennessee for “a young Tom Hanks with light eyes and a quirky disposition.” The casting team particularly taken by his thick Southern accent, he was selected to play the role of young Forrest Gump in the movie adaptation of Winston Groom's 1986 novel. As part of his preparation to play the character as an adult, Tom Hanks worked to emulate Humphreys's speech and mannerisms.

Alongside his Forrest Gump costars Hanna Hall and Haley Joel Osment, he received a nomination at the 16th Youth in Film Awards, though he was ultimately bested in his category by Matthew McCurley from the movie North. Save for high school productions and an uncredited role in the 2003 television adaptation of the John Grisham novel A Painted House, Humphreys did not pursue a further career in acting.

As of 2008, he was studying at the University of North Alabama. In 2011, he played the role of "Eddie" in the independent World War II film Pathfinders: In the Company of Strangers.