Haggard was born during the Great Depression in a remodeled boxcar where his family lived in Oildale, California.

His father died of a brain hemorrhage in 1945, an event that deeply affected Haggard during his childhood and the rest of his life.

When Merle was 12, his brother Lowell passed down his used guitar. Haggard learned to play alone, with the records he had at home, influenced by Bob Wills, Lefty Frizzell, and Hank Williams.

In "Mama Tried", Haggard focuses on the pain and suffering he caused his own mother by being incarcerated in 1957.

His debut performance was with his friend Bob Teague in a Modesto bar named "Fun Center", for which he was paid US$5 and given free beer.

He was arrested in 1957 shortly after he tried to rob a Bakersfield roadhouse. He was sent to Bakersfield Jail, and after an escape attempt, was transferred to San Quentin Prison on February 21, 1958. While in prison, Haggard learned that his wife was expecting another man's child.

Throughout his career, Johnny Cash performed in prisons, sympathetic to the plight of inmates who ran afoul of society. Haggard would attribute a performance by Cash at San Quentin on New Year's Day 1959 as his main inspiration to join the prison band.

In 1967, Haggard recorded "I'm a Lonesome Fugitive", written by Liz Anderson, with her husband Casey Anderson, which became his first number-one single. When the Andersons presented the song to Haggard, they were unaware of his prison stretch.

In 1972, after Haggard had become an established country music star, then-California governor Ronald Reagan granted Haggard a full pardon.

Haggard wrote "Okie from Muskogee" after he became disheartened watching Vietnam War protests. "We were in a wonderful time in America," he said, "and music was in a wonderful place. America was at its peak, and what the hell did these kids have to complain about? These soldiers were giving up their freedom and lives to make sure others could stay free. I wrote the song to support those soldiers."