Knocker was born in
Exmouth,
Devon, the youngest of six children of Royal Navy officer Hugh Horatio Knocker and Rosa Hensley (sister of
Prince Edward Island politician
Joseph Hensley). When Knocker was born her father was patrolling the coast of
West Africa as commander of the gun vessel . He died of a fever at sea four months after Knocker's birth. Knocker studied the violin with
Joseph Joachim in
Berlin from 1889 to 1890. Upon her return to England she settled in York, where her mother lived, and taught at various schools, including
The Mount School. A diagnosis of
neuritis in her arm thwarted her plans for a career as a solo performer. == Teaching career ==