Born in Fort Worth, Texas in 1948, Dowd's family moved to Memphis, Tennessee in 1950, and then to his father's hometown of Pauls Valley, Oklahoma in 1953. He received a record player for Christmas in 1956 and began buying records at a local appliance store. Although the first LP he owned was by the Ray Conniff Singers, it was the music of Hank Williams, Elvis Presley, Ray Charles and James Brown, that changed his life. He cites James Brown's Live at the Apollo as his lifelong favorite album.
In 1965, along with his mother and sisters, Johnny returned to Memphis after his parents' divorce. After serving in the U.S. Army and living in California he drove across the United States in the early 1970s with longtime friend Dave Hinkle and settled permanently in Ithaca, New York where his mother and sisters had also relocated. Dowd and Hinkle began moving furniture for a living, later naming their business the Zolar Moving Company.
Dowd formed a band in the 1970s named The Jokers, which included Johnny (guitar), his sister Jennifer Edmondson (drums) and Dave Hinkle (bass). By 1988, the band had become Neon Baptist, who in addition to Dowd included Cally Arthur, Dave Hinkle, Mike Edmondson and Jennifer Edmondson, with Max Ormond and Kim Sherwood-Caso joining the band in later lineups. Neon Baptist was one of the founding acts of the GrassRoots Festival, where Dowd has performed annually since 1991.
By the time Neon Baptist disbanded in 1995, Dowd was recording songs alone in the office of his moving company. These songs first appeared in 1995 on a home-made demo cassette as Wrong Side of Memphis, which credited Dowd as a solo artist and featured Kim Sherwood-Caso on background vocals on two songs. Most of these tracks were either re-mixed or completely re-recorded for the CD version of the same album, which was initially pressed as a self-released CD and then officially released on Chicago's Checkered Past label in 1997. The album was also released on Koch Records in early 1998 and then in Europe on Munich Records. Favorable reviews led to some of his first European appearances in 1998.
In the wake of the critical acclaim for Wrong Side of Memphis, Dowd released his second album, Pictures From Life's Other Side, in 1999, also to positive reviews. That year also saw the first of Dowd's US and European tours. After the self-released, experimental Down In The Valley in 2000 came Temporary Shelter. A Dutch TV documentary on Dowd was filmed in 2000, and in early 2001, the New York Times highlighted him as one of four "Country Singers Who Still Display a Country Heart".
Dowd's The Pawnbroker's Wife album was released in 2002, followed by Wire Flowers: More Songs from the Wrong Side of Memphis in 2003. That same year, he was handpicked by The Simpsons' creator Matt Groening, a self-described fan of Dowd's music, to perform in the All Tomorrow's Parties festival. He also made his major film appearance in 2003 with Searching for the Wrong-Eyed Jesus. The album Cemetery Shoes was released in 2004. Cruel Words, released in 2006, went on to win the Alt Country award in the 7th Annual Independent Music Awards the following year.
In 2006, Dowd, drummer Brian Wilson (aka Willie B) and Jim White formed the band Hellwood. Their album, Chainsaw of Life, was recorded in a cabin in New York, the walls of which were covered in musician obituaries. Hellwood toured the album in Europe. In April 2007, Dowd joined Beukorkest, a collaboration of various Dutch musicians and artists, for a nine-show tour of the Netherlands. In 2008, after an album of tracks from the tour was released, Beukorkest re-formed with a new team of musicians.
Dowd released A Drunkard's Masterpiece in early 2008 in the U.S., Canada and Europe, followed by a European tour in April and May. In October, he formed the trio Black Elastic with former band mates Kim Sherwood-Caso on guitar and vocals and Mike Edmondson on guitar. After several shows in the Ithaca, New York area, an expanded Johnny Dowd band was formed, composed of Sherwood-Caso, Mike Stark (keyboards), Matt Saccuccimorano (drums) and Willie B (baritone guitar). The group released its debut album Wake Up the Snakes in 2010. Dowd's solo-album That's your wife on the back of my horse was released in 2015 and featured on several tracks the singer/songwriter Anna Coogan from Ithaca.
In 2009, Dowd was also a judge for the 8th annual Independent Music Awards to support independent artists' careers.