In 1973, Lokko was posted to the Accra Academy to do her National Service. In 1974 she was appointed a permanent teacher of English in the school after her service. For the next seven years, she taught in Accra Academy as a tutor of English Literature. In 1981, Lokko was appointed the Head of the English Department of the school, a position she held until 1990 when she was appointed the Assistant Headmistress, Administration to the then headmaster V. B. Freeman. She occupied this position until 1996 when V. B. Freeman went on retirement. and later appointed the substantive headmaster in 1997, becoming the first woman and non-old student to head Accra Academy. During her headship of Accra Academy, she occupied the positions of Greater Accra Regional Chairperson of the Conference of Heads of Assisted Secondary Schools (CHASS) and subsequently National Treasurer of CHASS. She also supported her students to raise funds for the
National Cardiothoracic Centre in 1997. In 2005, Lokko handed over the position of headmaster to Samuel Ofori-Adjei and left Accra Academy. In September 2010, Lokko went on retirement from the Ghana Education Service. ==Personal life==