Her father was ordained in the United Free Church, and at the time of her birth, was the Chaplain to the Presbyterian members of the University of Oxford.

[2] Lusk started her career in social work at Edinburgh Children's Holiday Home, and in 1957, she began as a caseworker in the Edinburgh-based voluntary organisation, the Guild of Service for Women, working with unmarried mothers and their children and adoptive parents.

As Director she pioneered social work practice in adoption, residential child care and single-parent families.

[1][2] In the 1970 Birthday Honours, she was appointed an Officer of the Order of the British Empire (OBE) for services to child care.

[2][5] On retiring she was appointed Convener of Scottish Council for Voluntary Organisations, the first woman to hold the position.