Mrs. Johnston is a Director of 1834 Investments Limited (formerly The Gleaner Company Limited) since April, 2000. She is the Corporate Affairs Manager at the Jamaica Producers Group Limited. She is a member of the board of the Jamaica Exporters Association and Honorary Consul of Costa Rica. She is also a member of the Jamaica Trade and Adjustment Team in the Ministry of Foreign Affairs and Foreign Trade. Mrs. Johnston was a former Galo Plaza Fellow at the Inter-American Dialogue in Washington D.C.