Career

She has written episodes of television series such as Alias, The O.C., Charmed and Criminal Minds. She has also co-produced two television shows: Charmed and Criminal Minds, as well as acting as a story editor on Alias and executive story editor on The O.C.

Messer began her career with the television series Alias in 2001 as a screenwriter. In 2002, she was promoted to story editor on Alias.

Messer, then in 2003-2004, wrote several episodes for the The O.C. and serving as executive story editors

She wrote one episode for Charmed in 2004.From 2004-2005, Messer was the co-producer of Charmed. From 2005 to present, she has been with the television series Criminal Minds as a screenwriter, producer, supervising producer, and executive producer. in 2010, Messer was named co-showrunner.

In 2011, she was named sole showrunner. In 2013, Messer re-signed her contract with Criminal Minds.

In 2014, Columbia Broadcasting System was looking for a spin-official

In 2015, Messer wrote the backdoor pilot episode Beyond Borders in the tenth season of Criminal Minds for which the spin-off Criminal Minds: Beyond Borders was created.