From 2001 to 2009, Mittal was on the faculty of the Department of Mechanical and Aerospace Engineering at George Washington University.

[2] Mittal is the founder and chief technical officer of HeartMetrics, Inc., a start-up that develops computational tools to help the treatment of coronary artery disease.

[4] The focus of Mittal's lab is on fundamental fluid mechanics phenomenon and numerical analysis.

Recent projects have focused on flow control,[5] flow-induced flutter,[6] flow-induced vibration,[7] biolocomotion,[8] biosensing, bioacoustics,[9] cardiovascular hemodynamics,[10] heart murmurs and thrombosis, gastric fluid mechanics,[11] and the flow physics of COVID-19.

[12] During his time at Johns Hopkins, Mittal has made significant contributions to many topics in fluid mechanics, spanning cardiovascular fluid dynamics, fundamental mechanisms of human and animal swimming, development of immersed boundary methods, iterative methods in scientific computing, bioacoustics, and turbulent flows.