Shelley grew up in Vienna. She lives in Vienna and raises her five-year-old daughter in her childhood home. She holds a Bachelor's Degree in Interdisciplinary Studied from Virginia Commonwealth University. She also holds a Master of Science Degree in Telecommunications from George Mason University.

Shelley worked as a tutor and professor from 2009 to 2014. She worked as a Tutor at George Mason University from 2009 to 2011. She worked as an Adjunct Professor at J. Sargeant Reynolds Community College for less than a year in 2012. She has also worked at Norther Virginia Community College for three years as an Adjunct Professor and Assistant Professor.

Shelley M. Mountjoy's campaign for becoming a Member of the City Council of Vienna is her first entry into politics.