Tammy was born and raised in a small rural town called Austinburg, Ohio, which according to Tammy was a perfect place to write a country song. There was also enough tragedy in Cochran's life to write a country song.
She was born in 1972 to Mabel and Delmar Cochran and was the third of three children. Tammy's two older brothers, Shawn and Alan were both born with the disease Cystic Fibrosis. Shawn died from the disease in 1980, at 15 and Alan died in 1991 at age 24. She soon became accustomed to listening to and singing the songs of Loretta Lynn and Barbara Mandrell. Encouraged and inspired by her brothers, Tammy realized that she preferred singing in front of an audience. For the next few years, Tammy sang at her family's local church, and then she entered a talent show contest and won. The next step for Tammy was to join a band. She joined a couple before making her own band called "TC Country" that played at fairs and weddings.
In 1998, Cochran met Shane Decker, a songwriter for Warner Bros. Records. He offered his help on making demos to send to record companies after seeing Cochran. He also helped her get a job as a songwriter for Warner Chappell. Her demo tapes were sent to Epic Records. She released her first single that same year called "If You Can", followed by "So What". Although neither single made Top 40 on the country charts, the third single ("Angels in Waiting", written about her brothers) peaked at No. 9, and its success led to the release of her self-titled debut album. The video for "Angels in Waiting" won a Christian Country Music Award for 'Video of the Year'. This album's fourth single, "I Cry", reached Top 20 as well.
Cochran's second album for Epic, Life Happened, was released a year later. The lead-off single reached Top 20, while "Love Won't Let Me", the follow-up, peaked at No. 31 and Cochran was dropped from Epic in 2003. Her third album, Where I Am, was issued on the independent Shanachie Records in 2007.
In 2014 she starred in a musical show entitled "One" at the Alabama Theatre in Myrtle Beach, South Carolina.