Heineman was a founding member of video game companies Interplay Productions, Logicware, Contraband Entertainment, and Olde Sküül.

[5] In 1980, Heineman and a friend traveled to Los Angeles to compete in a regional branch of a national Space Invaders championship.

Heineman, aged 16 at the time, moved across the U.S. for her new job, canceling her plans to acquire a high school diploma.

Heineman acted as lead programmer for the company, working on Wasteland, The Bard's Tale, Out of This World, and the Mac OS and 3DO ports of Wolfenstein 3D.

Projects led by Heineman include Myth III: The Wolf Age and Activision Anthology, and Mac OS ports for Aliens vs.

During this time, she also provided consultancy work directly for other companies: She acted as "Senior Engineer III" for Electronic Arts, upgraded engine code for Barking Lizards Technologies and Ubisoft, optimized code for Sensory Sweep Studios, acted as senior software architect for Bloomberg L.P. and Amazon, provided training on Xbox 360 development for Microsoft's development studios, and worked on the kernel code for the PlayStation Portable and PlayStation 4 at Sony.

[5] Contraband was wound down in 2013, and Heineman founded a new company, Olde Sküül, together with Jennell Jaquays, Maurine Starkey, and Susan Manley.

[1][8] Heineman resides in El Cerrito, California, where her company Olde Sküül is located.