His best-known works are the films Speed, Broken Arrow, and Hard Rain and the TV series Justified and Silo.

[1] He is the son of Canadian television personality Elwy Yost,[2] the longtime host of the public broadcaster TVOntario's Saturday Night at the Movies.

Yost wrote for the TV sitcom Herman's Head and the HBO miniseries Band of Brothers.

Yost teamed with Tom Hanks and Steven Spielberg, along with two of his fellow Boomtown writers Michelle Ashford and Larry Andries, to write and direct episodes of the HBO miniseries The Pacific.

Based on the Alex Kershaw book Avenue of Spies, it would be set in Nazi-occupied Paris at the start of World War II.