Hewitt got her first name from her older brother Todd (b. 1971), who picked then name for a little blonde girl he had a crush on. Her mother selected her middle name, Love, which she goes by offstage from her best friend at college. Her mother, Pat, is a speech pathologist and her father, Danny, is a medical technician. Her parents separated when she was six months old. Born in Waco, Texas, she was raised by her mother in Killeen. She made her official performing debut at age 3 where she sang at a livestock show.

At age 5, she was taking tap, jazz, and ballet lessons which led her to joining the Texas Show Team, which toured the Soviet Union and Europe. At age 10, the family moved to L.A. with the encouragement of talent scouts, while Todd stayed behind to finish high school in Texas. Love quickly found commercial work and a role on Disney's "Kids Incorporated". She went through a series of television flops before finally hitting it big on "Party Of Five" in 1995.