Australian country singer Mack Geiger has gone from studying to be a paramedic and working on a cattle ranch to landing his debut on the Billboard Hot 100, all within roughly eight months. His breakthrough single "String By" has reached No. 48 on Billboard's Country Airplay chart, marking a rapid rise for the Queensland-raised artist who has been named Billboard's Up-and-Coming Country Artist for September.

Geiger grew up on his family's cattle station and later worked on a larger ranch while performing cover sets at local bars. He released "String By" in October 2025 and signed with RECORDS Nashville/Columbia Records earlier this year, since following up with tracks including "Pouring" and "Campdraft Queen". Over the past year he has made his debut at the Grand Ole Opry and Nashville's CMA Fest, played Australia's CMC Rocks, and completed his first US headline tour, with further new music now in the works with producer Keith Stegall.