Gary Parker began his musical career as a first soprano soloist with the Texas Boys Choir. With them he sang on the Pat Boone and Today national television shows, at New York's Town Hall, London's Westminster Abbey, Notre Dame Cathedral in Paris and High Mass at St. Peter's Cathedral in Rome. After his voice changed he toured for four years with the Austin College a capella choir. He also played the lead role in the all college musical and formed a barbershop quartet called the Four AC's.
As a BHS member he has performed and competed over fifty years in several prominent quartets, most notably Dealer's Choice (DC), the only quartet over the last 65+ years to win the BHS championship in their first international competition.
He is a charter and still active member of Dallas' decorated Vocal Majority Chorus (VM) and has served over the years in a variety of roles, including music staff, bass section leader, assistant director and Music VP. He was also music director and primary arranger for the Virginians Chorus in Richmond for eight years, during which he composed a Virginia "state" song grand finalist.
He served on the BHS international board of directors and three consecutive terms as president of the Association of International Champions. He authored the Amazon books One and Done, Dealer's Choice Quartet Overnight Success Story and Basic Group Singing Techniques, A Primer For the Amateur Singer. He is in the Southwestern District (SWD) Hall of Fame and the DC is in the BHS and SWD Halls of Fame and the VM Ring of Honor.
In a 2016 informal survey of barbershop harmony experts, he was listed as one of the top ten barbershop basses of all time.