Guðný holds an MBA degree in International Business from San Diego State University and a BS degree in Hotel Management from the University of Nevada, Las Vegas. For the past sixteen years, she has held various leadership positions at Icelandic companies. Guðný has been involved in financial management, optimization, strategic planning, project management and diverse human resource projects. 

Guðný was the CEO of Sagafilm from 2015-2017, Sagafilm's CFO from 2007-2015, and financial director of Vodafone Iceland from 2001 to 2007. Prior to that time, she worked for the hotel industry for many years. Guðný has served on the board of various companies, in Iceland, Scandinavia and UK.