After graduating, she continued as a commercial artist in the Los Angeles area for fifteen years before semi-retiring to start a family.

After that, she had several part-time jobs while continuing to write historical novels, including tasting host and tour guide for a local winery, choir director and soloist for a church, theology teacher, and secretary.

[citation needed] In October 2011, Minotaur Books published her fourth medieval mystery entitled Troubled Bones.

[3] In October 2012, her fifth, Blood Lance was released and was named one of the “Ten Hot Crime Novels for Colder Days” by Kirkus Reviews.

In 2011, author Tim Hallinan asked Westerson to participate in a short story e-book anthology whose entire proceeds would raise money for Japan earthquake relief.

[citation needed] The book, called Shaken: Stories for Japan, includes nineteen other authors, such as Brett Battles and Ken Kuhlken.

Her gay erotic short story under the name Haley Walsh, "Marked," was included in the anthology Anything for a Dollar, edited by Todd Gregory, released October 15, 2013.

[citation needed] She is also a founding member of the Los Angeles chapter of the Historical Novel Society and other professional writing organizations.