Born circa 1876 on the Isle of Skye to William Watson, a shepherd, and Margaret "Peggy" Ross.

By the 1901 census Elizabeth was listed as living in Govan, Glasgow, and working as a domestic table maid. She married Andrew  Emslie Johnston, a plumber from Aberdeen, in Glasgow in 1902 and the couple moved to Croydon, Surrey, England. They had two children, William Andrew and Catherine Nellie. 

The family made plans to emmigrate to the US in October 1911 on board the Philadelphia but with difficulties caused by the coal strike they decided to wait for Elizabeth's sister, Margaret and her family, and rearranged their journey on the Titanic. 

The entire party was lost in the disaster and none of their bodies were ever recovered.