Born Vivienne Darling in Dublin to Dr. Desmond Darling and Audrey Darling (née Butler), she had three sisters. McKechnie attended The Hall School, Monkstown, and then got her degree in Trinity College Dublin. Later McKechnie completed her Creative Writing MA in the University of Limerick. She went on to become a teacher and spent four years in Kenya before moving to Limerick. McKechnie wrote and began to have her poems published. Her debut collection was published in 2013. At least one of her works has been the poem on the Irish Leaving Certificate exams. McKechnie was also selected for inclusion in the "Windharp Poetry Anthology" for the centenary of 1916.