In film, she is best known for her roles as Mother at Farm House in Rain Man (1988), Miss Kettlewell in Child's Play 2 (1990), Helen in Speed (1994), Loretta in To Wong Foo, Thanks for Everything!

Julie Newmar (1995), Cora Mae Cobb in A Time To Kill (1996), Kitty Farmer in Donnie Darko (2001), Pageant Official Jenkins in Little Miss Sunshine (2006), Carla Jean's Mother in No Country for Old Men (2007), and Peppy's maid in The Artist (2011).

She starred in the films Flatliners, Sordid Lives, Dear Lemon Lima, Bad Words, Jackie (as Lady Bird Johnson), Faults (2014) and Lucky (2017).

Julie Newmar; Love Field; Donnie Darko; A Time to Kill; Little Miss Sunshine; Child's Play 2; Daltry Calhoun; City Slickers II: The Legend of Curly's Gold; Don't Tell Her It's Me; Matchstick Men; Factory Girl; The Wizard; Sordid Lives; The Rookie; All About Steve; No Country for Old Men, Extract, Crazy Heart, Rango, Hollywood to Dollywood (as herself), and Dance with Me.

Grant has appeared in many TV shows, including Coach; Everwood; Delta; The Golden Girls; Malcolm in the Middle; The X-Files; Friends; CSI; Six Feet Under; Wonderfalls; Pushing Daisies; My Name Is Earl; Yes, Dear; King of the Hill; The Office; Angel; Judging Amy; Jericho; Sordid Lives: The Series; Criminal Minds, Sabrina The Teenage Witch; True Blood; How I Met Your Mother; Modern Family; The Mentalist; and The Mindy Project.