Country music icon Merle Haggard dies on 79th birthday

(CNN)Merle Haggard, the grizzled country music legend whose songs, such as "Okie from Muskogee" and "Fightin' Side of Me," made him a voice for the workingman and the outsider, has died. He was 79.

Haggard died Wednesday, his birthday, of complications from pneumonia at his home in Northern California, his agent Lance Roberts told CNN.

Haggard recorded more than three dozen No. 1 country hits in a musical career that spanned six decades, from the 1960s into the 2010s. He overcame an early life of petty crime and a prison term in San Quentin to develop a rugged, outlaw image that helped sell millions of records.

Tributes immediately began pouring in from the country music world and beyond.

"Country music has suffered one of the greatest losses it will ever experience," said country star Charlie Daniels on Twitter. "Rest in peace Merle Haggard."

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

"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," said singer Brad Paisley.