The 52-year-old ophthalmologist has founded an eye clinic for low-income patients and once stood on the Senate floor for nearly 13 hours. Here's what else you might not know or remember.
The Republican senator from Kentucky looks to get a jump on what is likely to be a crowded GOP field in 2016. Polls show him in a three-way tie for third place for his party's nomination.
As Rand Paul embarks on a presidential campaign, he doesn't fit into the mold of either party neatly. Especially on foreign policy, the Kentucky senator faces a challenge.