Steinbacher was born in Munich on November 14, 1981, to a German father and a Japanese mother. When she was three, her mother read that a German violin teacher had recently returned from Japan after studying the Suzuki method. Steinbacher started violin lessons at that time. When she was nine years old, she was enrolled at the Munich College of Music and mentored by Ana Chumachenco.
Steinbacher came into contact with Ivry Gitlis, and took part in master classes by Dorothy DeLay and Kurt Sassmannshaus in Aspen, Colorado. She won several important prizes (the Joseph Joachim International Violin Competition in Hanover), and a grant from the Free State of Bavaria in 2001, then became a student of Anne-Sophie Mutter's Freundeskreis ("Circle of friends").
She has recorded extensively for PENTATONE and Orfeo.