Helen Greiner was born in London in 1967. Her father came to England as a refugee from Hungary, and met his wife, Helen's mother, at the University of London. When Helen was five, her family moved to Southampton, New York. At the age of ten, Greiner went to see the popular film Star Wars and has said she was inspired to work with robots by R2-D2 in the film. Greiner graduated from the Massachusetts Institute of Technology in 1989 and earned her master’s there in 1990.

In 1990, along with Rodney Brooks and Colin Angle, Greiner co-founded iRobot, a robotics company headquartered in Bedford, Massachusetts, which delivers robots into the consumer market. She co-designed the first version of the iRobot Roomba.

Greiner served as President of iRobot (NASDAQ: IRBT) until 2004 and Chairman until 2008. During her tenure, iRobot released the Roomba, the PackBot and SUGV military robots. She built a culture of practical innovation and delivery that led to the deployment of 6,000 PackBots with the United States armed forces. In addition, Greiner headed up iRobot’s financing projects, raising $35M in venture capital for a $75M initial public offering. She has worked at NASA's Jet Propulsion Laboratory and the MIT Artificial Intelligence Laboratory.

Greiner was recently CTO of CyPhy Works, home to the Persistent Aerial Reconnaissance and Communications (PARC) and Pocket Flyer multi-rotor drones. She also served on the board of the Open Source Robotics Foundation (OSRF). As of 2018, she works as an advisor to the United States Army.