McRaney was born in Collins, Mississippi, the son of Edna and Clyde McRaney, a builder. He is of Scottish and Choctaw Indian ancestry. He attended college at the University of Mississippi. Before hitting it big as an actor, McRaney worked in the Louisiana oil fields.
McRaney holds the distinction of being the last guest star to meet Marshal Matt Dillon in a gunfight on Gunsmoke, in the episode "Hard Labor," which was first broadcast on February 24, 1975. He starred in 1969's Night of Bloody Horror, a low-budget slasher film in which he played the lead character Wesley Stuart. Gerald participated in the Dukes of Hazzard series in the episode "Hazzard Connection" (November 9, 1979). He played a receptionist in two different episodes of The Rockford Files and a heroin-addicted Vietnam War veteran in one episode of Hawaii Five-O. In addition, he starred in numerous episodes of The Incredible Hulk playing roles as a jealous boyfriend, an evil race car driver, and an angry police officer. He played an unnamed town local in the miniseries Roots: The Next Generations. However, McRaney is perhaps best known for his role as Rick Simon in the 1980s television show Simon & Simon. He also had starring roles on Major Dad and Promised Land, and a recurring role on Designing Women. McRaney portrayed General Alan Adamle in two episodes of the NBC drama The West Wing. He played a prominent role in the third season of the HBO television series Deadwood, as famed gold prospector George Hearst. McRaney had a starring role in the CBS post-apocalyptic series Jericho as Johnston Green. In addition, he has acted in many television films such as Not Our Son (1995), Going for Broke (2003), as General George S. Patton in Ike: Countdown to D-Day (2004), and appeared as Dan's father in One Tree Hill. He starred in an episode of CSI: Crime Scene Investigation and Diagnosis: Murder (Episode 1.13 "Lily") as Det. Andy Ruggio, appeared in the 2005 music video for Fall Out Boy's "Sugar, We're Goin Down".
In 1999 he starred in the film A Holiday Romance as Cal Peterson. In the late 2000s, McRaney co-hosted the cable outdoor hunting and shooting series (a McRaney hobby) "The World of Beretta", which featured rifle and shotgun products of the sponsor in a number of exciting hunting locations around the world; and often featured a celebrity shooter to hunt with McRaney. He starred as the villanous General Morrison in the 2010 film The A-Team.
In 2010 he played a recurring role as CIA handler Carlton Shaw in the NBC action drama Undercovers. In 2011, he began playing a recurring role as a judge on the USA drama Fairly Legal. In 2012 he played General Luntz in Red Tails & he played Calvin in Heart of the Country. Dec 2012 guest on Mike and Molly TV show.
He married actress Delta Burke on May 28, 1989, whom he had met two years earlier during her guest appearance on a Simon & Simon episode. She is his third wife. He also appeared on Designing Women as Dash Goff (who was named after a real person from Fayetteville, Arkansas, whom Delta Burke's fellow castmate, Annie Potts, had met while filming, "Pass the Ammo" on location).
He played a Marine Corps veteran on Simon & Simon and a Marine Corps officer on Major Dad, and has always been very supportive of veterans and soldiers, though he is not a veteran himself. He made many visits to support the soldiers in Operation Desert Storm. During one USO-sponsored trip, McRaney visited sailors and Marines onboard ships ported in Toulon, France on Thanksgiving of 1993. He signed autographs for the men on board the ships. While on board the USS Ashland, he autographed one sailor's cowboy hat. He visited troops during Operation Restore Hope in Somalia in 1993.
Politically he is a conservative Republican. and a member of the National Rifle Association.
In September 2004, McRaney was treated surgically, and apparently wholly successfully, for lung cancer in Houston, Texas.
In 2010 he was the host of a cable series on Spike TV encouraging viewers "Don't be a Victim" titled: "Practical Tactical", "What If", "Because Lives Depend on it", and "Concealed Carry School". One episode highlighted an instance where his lifelong friend and Simon & Simon costar Jameson Parker was shot twice.