Witkin received a B.A. in Psychology from Columbia College in 1975 and a Ph. D. in Psychology from M.I.T. in 1980. He then joined the Schlumberger Palo Alto Research Laboratory, where he led a research program in computer vision and graphics. At Schlumberger, Witkin developed the technique of "Scale-Space Filtering," now a classic method of analyzing signals with important features at different scales.

Witkin was one of the first to recognize the importance of the relationship between computer vision and computer graphics --- they are essentially inverse problems. In computer vision, one shows the computer a picture and asks it to infer what is there. In computer graphics, one tells the computer what is there, and asks it to create a picture. Nonetheless, in the early 80s, the vision and graphics research communities were largely disjointed. Witkin bridged the gap in a series of landmark papers that he co-authored, included his 1987 prize winning paper "Constraints on deformable models: Recovering 3D shape and non-rigid motion" and "Snakes:
active contour models". (According to CiteSeer, the Snakes paper is the eleventh most cited computer science paper.) These papers popularized the idea that computer vision techniques could provide interactive "power assists" to a human operator creating computer graphics models. In 2001, he was honored by ACM SIGGRAPH, the main computer-graphics professional society, with the prestigious Computer Graphics Achievement Award for the depth and breadth of his accomplishments.

In 1988, Witkin became a professor at Carnegie Mellon University where he taught for 10 years, training a group of students who have in their turn become influential researchers. At Carnegie Mellon, his interests turned towards problems of producing computer graphics using physically based simulation. In 1988 Witkin's "Spacetime Constraints" paper introduced the idea of using control theory in computer graphics to produce compelling animated characters. In 1992, he won the Golden Nica Award from Ars Electronica for an art piece created using simulated chemical reactions to synthesize organic looking textures.  In 1998, Witkin joined Pixar and began working on a series of ground-breaking technologies used in the production of Pixar films. Specializing in the use of simulated physics in animation, he developed software to create realistic movement of virtual clothing, hair, fur and water that were instrumental in creating the characters in “Monster's, Inc.”, “The Incredibles,” and other films. In 2006, he was honored by the Academy of Motion Picture Arts and Sciences with an Academy Award for "pioneering work in physically-based computer-generated techniques used to simulate realistic cloth in motion pictures." He recently developed new techniques for simulating hair in the upcoming Disney/Pixar feature film “Brave.” “We will always have Andy to thank for the life and energy his work has brought to our characters” says Bill Wise, a Supervising Technical Director at Disney/Pixar. “Andy was a real pioneer in our industry and I feel very lucky to have gotten to work with him over the years. I worked closely with him first on “The Incredibles” and I know without his help we would not have had the amazing characters we did for that film. He loved the excitement of production and seeing his tools used to put beauty on the screen.”

A man of many interests, he enjoyed playing guitar and ukulele, gourmet cooking, and photography. Most of all, he valued time spent with his family. Witkin is survived by his wife Sharon and two college-age daughters, Emily and Anna. A memorial service will be held at 1pm October 2 at Chapel of the Chimes in Oakland, CA.