[2] Shannon was born into the Gilsenan family in County Meath, Ireland, as the middle child of five siblings.
In 1992, Shannon entered Dublin's College of Music and studied under the guidance of vocal trainer Mary Brennan.
She was cast into the role[citation needed] of Erin the Goddess and performed in over 800 shows over a four-year period covering most of North and South America.
Shannon's accomplishments have also included participating[citation needed] in the sound track of RTÉ's historical documentary television series called The Island.
Playing the role of the Gentlewoman, Shannon also sings "Harry's Game" as well as other songs in Celtic Thunder: Storm which was released on CD and DVD on 20 September 2011.