Lawson was born in Los Angeles, California. A member of the Gordy family, she is the daughter of Denise (née Gordy) and actor Richard Lawson making her the great-niece of Motown founder Berry Gordy.
She started acting at the age of nine when she appeared in commercials for Barbie.
She attended the Stella Adler Studio of Acting and graduated from Marymount High School. She then went on to study film and psychology at University of Southern California.
In 1993, Lawson was one of the original cast members of Saved by the Bell: The New Class, she also appeared in multiple episodes of The WB sitcoms Sister, Sister, The Parent 'Hood and The Steve Harvey Show.
She is perhaps best remembered by genre fans for her stint on Buffy the Vampire Slayer. Lawson portrayed Kendra Young, another Vampire Slayer who is activated as a result of Buffy's temporary death.
She also had a memorable role on Dawson's Creek playing Nikki Green, a principal's daughter and Dawson love interest in 1999.
In 2010, Lawson played Maya St. Germain in the ABC Family series Pretty Little Liars based on the book series by Sara Shepard until her character was killed of at the end of Season 2.
She later portrayed the witch, Emily Bennett, in another vampire-related series, The Vampire Diaries.
Some of Lawson's film credits include Primary Colors (1998), Save the Last Dance (2001), Bones (2001) and Breakin' All the Rules (2004).