She developed a real love for the art and signed with an agent at the age of 8. Sloane was a television series regular on Mr. Rhodes (1996) and had a recurring role on The Wonder Years (1988). She has also appeared in episodes of Dharma & Greg (1997), Working (1997), My So-Called Life(1994), That '70s Show (1999), The West Wing (2000), Greg the Bunny(2002), Entourage (2006) and How I Met Your Mother (2009), as well as the made-for-television movie, CBS Schoolbreak Special (1995). Sloane's theater experience included Emperor's New Clothes, Say Yo Ho Ho, Rumors and Cabaret.
She later played Valerie Birkhead on Sabrina, the Teenage Witch from 1997 to 1999, and starred in Sabrina Down Under, a spin off movie to the series as a different character, a mermaid named Fin.
In film, Sloane starred in Bring It On (2000), The In-Laws (2003), Over Her Dead Body (2008), She's Out of My League (2010), The Other Guys (2010), The Accidental Husband (2008) and Horrible Bosses (2011).