Introduced in September 1990, she was portrayed by several child actors until the character left the series in 1992, with further guest appearances in both 1996 and 1997.

Theresa is the daughter of supercouple Shane Donovan and Kimberly Brady (Charles Shaughnessy and, most prominently, Patsy Pease).

With the casting of Lilley in the role, the character entered her first major story line, opposite Casey Moss who portrays JJ Deveraux.

In April 2013, it was announced by Soap Opera Digest and several other sources that Jen Lilley joined the cast of Days of Our Lives in a newly created role with ties to the canvas.

"[32] Jeannie Theresa Donovan is introduced in September 1990, to Kimberly Brady (Patsy Pease), and was originally believed to be the daughter of Cal Winter.

[a][33] However, paternity tests and a confession from Cal proved her father to be Shane Donovan (Charles Shaughnessy).

Initially, she strikes up a connection with resident bad boy JJ Deveraux (Casey Moss) while trying to secure some pot.

[38] To continue to battle against Jennifer, she teams up with Anne Milbauer (Meredith Scott Lynn) in hopes of exacting her perfect revenge.

In a ploy, Theresa reveals her intentions to hopefully woo Dr. Daniel Jonas (Shawn Christian).

Theresa then teams up with hospital co-worker Anne Milbauer (Meredith Scott Lynn) to conspire against Jennifer, using Daniel as a way to hurt their relationship.

In early 2014, following a Narcotics Anonymous (NA) meeting, she begins a sexual and drugged-fused relationship with Brady Black (Eric Martsolf).

She eventually expresses her interest in purchasing Basic Black and running it as her own fashion company, with financial backing from Maggie Horton (Suzanne Rogers).

In the hopes of finding the right partner, she teams up with Kate Roberts (Lauren Koslow) and Nicole Walker (Arianne Zucker) to achieve the goal of purchasing Basic Black, with Kate and Nicole's business background and her own interest in fashion design.

[6] Despite rumors of Lilley joining the cast as a recast for either Belle Black or Cassie Brady, it was informed she would portray a new character.