Geoffrey S. F. Ling is a medical doctor who retired from the United States Army as a colonel and was the CEO of On Demand Pharmaceuticals.

He served as the founding director of the Defense Advanced Research Projects Agency (DARPA) Biological Technologies Office from 2014 until 2016.

[1] He was considered to be the "US Army's premier subject matter expert on traumatic brain injury (TBI)", and was for years the only neuro-intensive care specialist in the US military.

[2][4] On May 21, 2018, HARPA (Health Advanced Research Projects Agency) was first publicly proposed on Fox Business News by Bob Wright and Geoff Ling [1][usurped].

In April 2020, Ling co-wrote with Michael Stebbins the proposal for the creation this new federal agency modeled on DARPA, but focused on health.

He is married to Shari Ling, M.D., [2] the national Deputy Chief Medical Officer of the Centers for Medicare and Medicaid Services (CMS).

[7][8] Ling completed two war deployments as a neurointensive care physician: Afghanistan (2003) and Iraq (2005), as well as four "Gray Team" missions to study combat brain injuries.

[11] Prior to his position as the founding Director of the Biological Technologies Office at DARPA, Ling was Professor and Acting Chair of the Department of Neurology at the Uniformed Services University of the Health Sciences (USUHS).

[16][17] Earlier in 2014, DARPA's Biological Technologies Office announced the launch of a new Hand Proprioception and Touch Interfaces (HAPTIX) program, which aims to deliver naturalistic sensations to amputees and, in the process, enable intuitive, dexterous control of advanced prosthetic devices; provide the psychological benefit of improving prosthesis "embodiment"; and reduce phantom limb pain.