Mersiha began pursuing acting at the age of thirteen.
She first worked at a youth drama school — initially hired for her remarkable talent in making coffee, and soon invited to join the acting classes instead. Her first screen appearance came early on in a German biopic about Heinrich Heine. During her school years, she remained active in theatre and began writing her own plays.

After graduating, she studied acting at Schule für Schauspiel Hamburg. Following three years of training, she performed on stage in Hamburg and continued working in German television and film. In 2018, she moved to Munich and became part of the main cast of SOKO München, portraying a police officer. The series is currently on air.

For her debut feature film Cherry Juice, which she directed, wrote, and produced, Mersiha received two Best Actress awards.