Born in Tehran, Iran, Afsoon Roshanzamir Johnston was 11 years old when her family fled Iran in the early 1980s and settled in California.

Supported by her father, she gravitated towards wrestling and competed as a member of the Independence High School boys wrestling team. One of the first girls to wrestle on a boys varsity team in California she nearly qualified for the boys state high school tournament, a single-class tournament format, meaning all schools, regardless of enrollment size, compete together in one unified state bracket per weight class rather than being split into multiple divisions or classes like in many other states.

Just eight days after celebrating her 17th birthday and still in high school, Johnston won the bronze medal at the 1989 World Championships, the first to include women's wrestling alongside the men, to become the first American woman to win a World Championship medal and the first American woman to medal at any international wrestling championship.

She won a silver medal at the 1990 World Championships while finishing fifth in 1992 and competing in 1997. She was also a medalist in international competitions in Canada, France and Russia.

Johnston was also the first female rostered athlete on the men's varsity wrestling team at University of California, Davis.

She was named USA Wrestling Women's Coach of the Year after being a member of the coaching staff then led the United States to a third-place finish at the 2014 Women's World Championships. Johnston was a member of the U.S. coaching staff for the 2016 Rio Olympics, where Helen Maroulis became the first American woman to win a gold medal. She also coached Team USA at additional world championships, Pan American championships, Golden Grand Prix Finals, and the 2021 Captain's Cup.

A licensed wrestling official, Johnston made history when she officiated a UC Davis dual meet, becoming the first woman to referee an NCAA Division I men's wrestling match.

Johnston has served as a board member for USA Wrestling, Titan Mercury Wrestling Club, the New York Regional Training Center and the California Wrestling Hall of Fame. She also served on multiple USA Wrestling committees, including women's sports, sports, and diversity, equity and inclusion.

Throughout her career Johnston has helped shape policies and programs that strengthen opportunities for girls and women in wrestling. A widely respected ambassador for women's wrestling both nationally and internationally, Johnston has served as a mentor and role model for generations of female wrestlers and is known for advocating for athletes while maintaining integrity, professionalism and humility.

She received the Lifetime achievement award from the California Wrestling Hall of Fame and is a member of the Cal Aggie Athletics Hall of Fame, the San Jose Sports Hall of Fame, and the Independence High School Hall of Fame.

Wrestle Like A Girl established and annually presents the Afsoon Courage award.

One of the earliest pioneers of women's wrestling, Johnston has devoted her post-competitive career to ensuring future generations have greater opportunities than those available during her own career.