The face of Carol’s Daughter, a unit of L’Oreal SA, isn’t a singer, actress or model—but its founder, Lisa Price.

The line of beauty products was founded by Ms. Price in her Brooklyn, N.Y., home, where she developed lotions and hair products and sold them in neighborhood markets. L’Oreal promotes this as a point of pride: In video ads Ms. Price, who is still involved with the company, rides an escalator at L’Oreal’s New York office. Images show Ms. Price at a kitchen stove, in photographs alongside her mom and finally on Oprah...