[4] Factor is the founder and executive chairman[5] of IntraBio Inc., a commercial-stage biopharmaceutical company based in Austin, Texas[6] which developed levacetylleucine, commercially known as AQNEURSA, for the treatment of neurological manifestations of Niemann-Pick Disease Type C.[7] Factor is visiting senior fellow in entrepreneurship at the Department of Pharmacology, University of Oxford, U.K.[8][9] He was the John C. West Professor (Emeritus) of International Politics and American Government at The Citadel, The Military College of South Carolina in Charleston, South Carolina.

[11][12] Factor has written widely on economic and financial issues for publications including the Wall Street Journal, Christian Science Monitor, National Review, and other newspapers and has contributed to BBC, Fox News and Forbes magazine items.

His work includes shows such as A Little Life, Cabaret, A Streetcar Named Desire, Dr Semmelweis, The King and I, A Christmas Carol, Patriots, Macbeth, Wizard of Oz, Constellations, Cyrano, Oklahoma, Hills of California, The Curious Case of Benjamin Button, The Rocky Horror Picture Show, The Piano Lesson, Leopoldstadt, The Merchant of Venice, and Sunset Boulevard.

On September 24, 2024 the US FDA approved AQNEURSA™️ (levacetylleucine) for the treatment of neurological manifestations of Niemann-Pick disease type C (NPC) in adults and pediatric patients weighing ≥15 kg.

[22] In addition to his books, Factor has written widely on economic and financial issues for publications including the Wall Street Journal,[23][24] Christian Science Monitor,[25] National Review[26] and newspapers nationwide and was previously also a Fox News[27] and Forbes magazine[28] contributor.

[36][37] He has testified in front of the U.S. House of Representatives and the United States Senate on terror financing, regulation of the financial services industry and other economic issues.