Maynard-Casely obtained her MSc in Planetary Science from University College London in 2005.
She received a Doctor of Philosophy in High Pressure Physics from the University of Edinburgh in 2009 for her thesis titled "The new mineralogy of the outer solar system and the high-pressure behaviour of methane".
[2][3] After completing her studies, Maynard-Casely held a postdoctoral research position at the University of Edinburgh until 2010.
[4][5] As of October 2022[update], she is an Instrument Scientist at the Australian Centre for Neutron Scattering.
[5] Maynard-Casely regularly contributes to various online blogs and news outlets including Cosmos magazine and not-for-profit news publisher The Conversation where she is frequently an advocate for the improved participation of women in STEM fields.