Sonaly was born in Bangkok, Thailand, on February 17, 1973, and grew up in Hendersonville, North Carolina. She graduated from the University of North Carolina at Chapel Hill in 1991. While getting her undergraduate degree, she studied abroad through Northeastern University, performing underwater marine conservation research in the British West Indies. She graduated from the University of North Carolina at Chapel Hill School of Law in 1998. Sonaly was admitted to the Colorado Bar in 1998, and practiced commercial litigation, products liability, health and hospital law, antitrust and appellate law with a regional firm in Denver, Colorado, for four years. She was admitted to the Washington Bar in 2003, and practiced commercial litigation and antitrust in Seattle, Washington. Sonaly then moved to Charleston and was admitted to the South Carolina Bar in 2005. She is a member of the Colorado, Washington, South Carolina, and American Bar Associations. Her areas of practice include products liability, commercial litigation, health and hospital law, and medical malpractice.