Blackwell was born in 1936 in Corpus Christi, Texas. His family moved to California, where Dewayne and his brother Ron (writer of Sham the Sham & The Pharaoh's oldies radio staple "Lil' Red Riding Hood") followed their fiddle-playing father's lead and started performing in bars as teenagers.
Per MusicRow, Dewayne and Ron joined family trio The Blackwells from 1958-'61 and had their final single produced by pop tastemaker Phil Spector. The band split after Ron died in a motorcycle accident.
Blackwell's biggest career development in the late '50s came when The Fleetwoods scored a hit with one of his compositions, "Mr. Blue." It's since been covered by Bob Dylan, Bobby Vee, Bobby Vinton, Gary Lewis & The Playboys and even Brooks. The Fleetwoods also found success with Blackwell's "The Last One to Know."
After a solid run of pop songs, such as The Everly Brothers' "The Ferris Wheel," Blackwell turned his attention to country music.
Though Johnny Darrell's 1970 recording of "Mama Come'n Get Your Baby Boy" charted, it would be another decade before Blackwell made a lasting impact as a Nashville songwriter.
A flurry of successful co-writes with "Friends in Low Places" co-writer Earl Bud Lee and other collaborators brought us David Frizzell's Grammy-nominated No. 1 hit from 1982, "Gonna Hire a Wino to Decorate Our Home," plus Marty Robbins' "Honkytonk Man," Conway Twitty's "Saturday Night Special," The Kendalls' "Still Pickin' Up After You" and the T.G. Sheppard and Clint Eastwood duet "Make My Day."
Brooks, who'd also recorded Blackwell's "Nobody Gets Off in This Town," scored big in 1990 with his genre-altering tale of low brow meets high class that'd win both CMA and ACM Single of the Year honors.
Despite this career boost for Blackwell, only one more composition of his, "Yard Sale," would impact the Top 20 when released in 1992 as a Sammy Kershaw single.
Later in life, Blackwell owned a restaurant in Mexico named Senor Azul, which is Spanish for Mr. Blue.
He joined the Nashville Songwriters Hall of Fame in 2017.