Scarwid was born in Savannah, Georgia, the daughter of Elizabeth (née Frizelle)[3] and Anthony John Scarwid. She has three brothers. Diana moved to New York City at 17 to become an actress. She graduated from The American Academy of Dramatic Arts and Pace University simultaneously, completing the dual program as an honor student.[4]
Scarwid started the new century with the portrayal of Dianne Barrie in the TV movie Dirty Pictures (2000). The same year, she appeared as Michelle Pfeiffer's character's kooky friend in Robert Zemeckis's What Lies Beneath. In 2001, she guest-starred in Law & Order as a fingerprint analyst accused of manslaughter, and in 2003, she appeared as a prying mother in A Guy Thing. The same year, she portrayed Elke Alig, Michael Alig's enabling and neglectful German immigrant mother in Party Monster, the adaptation of James St. James's memoir Disco Bloodbath. The following year, she starred as Karen Tyler, a smothering mother in Wonderfalls. She returned to the Law and Order franchise with an appearance as a mother on the warpath after finding out her son is a victim of pedophilia in Law & Order: Special Victims Unit in the episode titled "Head".
In the mid-2000s, she had roles in Read Thread (2005), Valley of the Heart's Delight (2006); and Local Color (2006). The same year, she guest-starred as Jeanette Owens in Prison Break, following which she assumed the role of Isabel, a mysterious sheriff and island inhabitant in the TV series Lost. Consecutively, she assumed roles in episodes of other TV series, including Cold Case, Pushing Daisies, and Heroes. Nearing the end of the decade, she had roles on The Cleaner (2009) and Criminal Minds (2009).
^"Celebrities: Today's Birthdays". Milwaukee Journal Sentinel. August 27, 1997. p. 8. ProQuest260578020. Actress Barbara Bach is 50. Actor Paul Reubens is 45. Rock musician Alex Lifeson (Rush) is 44. Actress Diana Scarwid is 42. Rap musician Bobo (Cypress Hill) is 29.
^"Happy Birthday". The Atlanta Journal-Constitution. August 27, 2022. pp. C3. ProQuest2707161500. Country musician Jeff Cook is 73. Actor Peter Stormare is 69. Actor Diana Scarwid is 67. Gospel singer Yolanda Adams is 61.