Country music icon Merle Haggard has died at his home in California, aged 79. The Grammy award winning singer succumbed to pneumonia on his birthday, his manager Frank Hull confirmed to the Associated Press.

Haggard was born in Oildale, California, to Oklahoma immigrants who migrated west during the Great Depression. His father died when he was nine years old and as a young man Haggard was involved in petty crime, spending much of his teen years in reform schools.

In 1957, Haggard and a friend attempted to rob a café and he was sentenced to five years in San Quentin State Prison. Inspired by Lefty Frizzell and Johnny Cash who performed for the inmates, on his release in 1960 he vowed to turn away from a life of crime. Finding salvation in music, he quickly gained a reputation in the Bakersfield area as a singer and instrumentalist.

Dubbed "the Poet of the Common Man," his music reflected his early roots, capturing the American condition in his stories of the destitute, the working class, the outlaw and the heartbroken.

Merle Haggard
Kennedy Centre honorees Sir Paul McCartney, left, and Merle Haggard, centre, in conversation following the formal Artist\'s Dinner at the United States Department of State in Washington, D.C. on Saturday, December 4, 2010, with Mr. Haggard\'s wife, Theresa Ann Lane AFP/Getty

In a career spanning over 40 years he recorded dozens of albums and had 38 Number One country hits. His first Number One hit was 1966's "I Am a Lonesome Fugitive," followed by 1967's "Branded Man," 1968's "The Legend of Bonnie and Clyde" and 1968's "Sing Me Back Home" and "Okie From Muskogee." In total, he wrote over 100 songs with his longtime recording and touring band, the Strangers, many of which have been recorded by the likes of Dolly Parton and The Byrds.

As well as three Grammy Awards he won dozens of county music awards throughout his career. Haggard won the Academy of Country Music's Top Male Vocalist award four years in a row, and was named Entertainer of the Year in 1970.

In 1972, Ronald Reagan, then Governor of California, pardoned Haggard for the attempted burglary charge that saw him serve time in San Quentin. A decade later, Haggard would perform at the White House. Reagan called Merle Haggard's music "the heart and soul of America."

In recognition of his accomplishments he was inducted into the Country Music Hall of Fame in 1994. In 2010, Haggard was among several artists, including Sir Paul McCartney, to be honoured at the White House by President Barack Obama at the annual Kennedy Center Honors.

Merle Haggard
John Hamlin, Jason Aldean, Keith Urban, Miranda Lambert, Merle Haggard, Tyler Hubbard of Florida Georgia Line, Larry the Cable Guy, and Brian Kelley of Florida Georgia attend the 2014 CMT Artists Of The Year at the Schermerhorn Symphony Centre on December 2, 2014 in Nashville, Tennessee AFP/Getty

Haggard never stopped touring. In the nineties, he summed up his career as "a thirty-five-year bus ride. He was still performing through to 2015, with his last tour spanning 20 venues.

Haggard was married five times. In 1993, Haggard married Theresa Ann Lane. They married in 1993, had two children and remained married until Haggard's death. He died at his home in California. No cause of death has been disclosed at this stage. As news of his death broke on Wednesday evening (6 April), tributes flooded in from fans and friends in the music industry.

A remembrance book set out below Merle Haggard\'s plaque at The Country Music Hall of Fame

— Natalie Neysa Alund (@nataliealund) April 6, 2016

Love and prayers for the Haggard family. Merle was a pioneer...a true entertainer...a legend. There will never be another like him.

— Carrie Underwood (@carrieunderwood) April 6, 2016

There are no words to describe the loss & sorrow felt within all of music with the passing of Merle Haggard. Thank God for his life & songs.

— Brad Paisley (@BradPaisley) April 6, 2016

Unbelievably sad to hear of Merle Haggard\'s passing. What a mark he left on country music. Forever grateful for that. ❤️

— Cassadee Pope (@CassadeePope) April 6, 2016

Merle Haggard is the reason I do what I do. I can\'t believe he\'s gone.

— Josh Thompson (@TheJoshThompson) April 6, 2016

Merle Haggard may you find peace and love in your next life.

— Tommy Chong (@tommychong) April 6, 2016

Merle Haggard was the best country songwriter there ever was.

— Jason Isbell (@JasonIsbell) April 6, 2016

My heart is sad with the passing of Merle Haggard. He wrote many songs that were part of the soundtrack of my life #MakeItThroughDecember

— Sr (@PapaJonas) April 6, 2016

Merle Haggard
Your name will be honored. Your music celebrated. Your legacy never forgotten. Country music will live on. I\'ll be sure of it.

— Granger Smith (@GrangerSmith) April 6, 2016

RIP Merle. I was proud to know you and have you as a friend. You gave the world some of the greatest country music ever written and sung.

— Larry The Cable Guy (@GitRDoneLarry) April 6, 2016

I\'ll tell ya what will never die...

— Larry The Cable Guy (@GitRDoneLarry) April 6, 2016

Sad day for country music! Merle Haggard is the greatest of all time...period! RIP Merle

— Craig Campbell (@craigcampbelltv) April 6, 2016