David O is an educator, physician, attorney, and ethicist. A lifelong Democrat, he has practiced both medicine and law, and he teaches health law and constitutional law at the UNLV William S. Boyd School of Law.

Nationally recognized for his expertise in medical ethics and health policy, David O has testified before Congress, had his scholarship cited by the U.S. Supreme Court, and has served on many national, state, and local commissions. In 2008, he served as a health policy adviser for the presidential campaign of Barack Obama and worked on the health plan that eventually became the Affordable Care Act..

While directing the medical ethics program at the American Medical Association, David O drafted the AMA's first ever Patients' Bill of Rights. He also wrote conflicts of interest guidelines that protect the integrity of the patient-physician relationship.

A graduate of Harvard Medical School and Harvard Law School, David O has written many books and articles on a wide range of topics in ethics, law, and medicine.

When he lived in Indiana, David O served for six years in the Indiana House of Representatives and earned respect on both sides of the aisle for his ability to find innovative solutions for the state’s pressing problems. He authored legislation to lower the cost of health care insurance, protect children from abuse or neglect, and increase funding for start-up companies so they can create new jobs. He was named "Best Politician of the Year" by Indianapolis' weekly newspaper NUVO for his work on property tax reform, reproductive rights, and equality for all persons. He also was recognized by Planned Parenthood with its Distinguished Legislative Service Award for his “strong and tenacious support” of the Planned Parenthood mission.