Dr. Zacharia serves as Associate Laboratory Director, Computing and Computational Sciences at the Oak Ridge National Laboratory (ORNL). The Computing and Computational Sciences directorate includes the Computer Science and Mathematics Division, the Computational Sciences and Engineering Division, and the Networking and Computing Technologies Division.

He directs the Center for Computational Sciences and leads the development and implementation of ORNL's high performance computing strategy. This strategy includes the development of topical user centers for high performance computing, the strengthening of ORNL's computational and networking infrastructure, and continued leadership in terascale computational applications, algorithms, and hardware.

His vision and efforts led to the acquisition of ORNL's terascale computing facility, making the Laboratory home to the most powerful nonclassified computers in the nation; thus greatly increasing ORNL's capability to support advanced climate modeling and genome research for DOE and transportation modeling for DOT and industry.