Born Gary Allan Herzberg in La Mirada, California, he started performing with his father and brother in a family band called The Herzbergs in venues around Southern California. He recalled to American Songwriter magazine: "I got my start at age 11 singing in bars and town halls, playing bass in a country band with my father and brother. We did old school country. Eventually I started singing, too."
He received his first record deal offer at the age of 15. Allan's parents made him turn it down, saying he wasn't ready.
Allan got his first tattoo at the age of 15. His mom cried and said it made him look like a criminal.
A concert by the Highwaymen (Waylon Jennings, Willie Nelson, Johnny Cash and Kris Kristofferson) inspired Allan to pursue music that reflected the dangerous side of life. "They were so powerful," he said. "It was like punk rock to me. It was so hardcore. I really, really wanted to be a part of that lifestyle."
Allan started pursuing a Country career in earnest in his 20s, selling his construction company when he was on the verge of signing a record deal. It fell through however, and he took a job selling cars. Allan left a demo tape in the glove box of a truck purchased by a wealthy couple, who listened to it and returned to the dealership raving about the music. "I told them it was me and I'd had a contract that fell through so I was saving money to go to Nashville and make a demo," Allan recalled to the Kansas City Star. "The wife asked how much that would cost. I said $10,000 to $12,000. Then the husband taps his wife on the shoulder and says, 'Write him a check,' which she did for $12,000. I gave it back and said I didn't want to feel like I owed them anything if it didn't work out. They just laughed and gave it back to me."
This independent funding allowed Allan to go to Nashville to record some of the songs that were on that early demo tape and sowed the seeds for his first record deal with Decca, Nashville.
Allan's debut album Heart for Sale peaked at #20 on the country chart and produced a Top 10 country hit with his cover of the Waylon Jennings song, "Her Man."
Allan's third wife Angela Herzberg shot and killed herself around 1 am on October 25, 2004 in their Tennessee home. She had been suffering from migraines and depression since the couple's move to Nashville the year before. Allan's 2010 song "No Regrets
" finds him opening up to moving forward since Angela's tragic suicide, while admitting, "I still miss her every day." He told Country Weekly
, "She always wanted me to write songs about her, but I never did back then. Now, I write all sorts of songs about her."
He had extensive vocal surgery in January 2011 to remove a polyp from his vocal cord. The operation was a success. "I don't think I realized it at the time, but there were a few years where I couldn't hit the falsetto notes, like the ones in 'Smoke Rings in the Dark,'" Allan recalled. "After the surgery, it was like I was 18 again."
Allan's ninth LP, Set You Free, was his debut #1 on the Billboard 200. It was the first time that an artist named Gary had topped the album chart.
Allan and his partner, Molly Mae Martinez, moved in 2021 into a house that used to belong to country legend Conway Twitty.