By age 13 she had begun her acting career, voicing a character in the CBS animated special "Why, Charlie Brown, Why?" in 1990. The following year she began a two-season recurring role on the nostalgic ABC sitcom "The Wonder Years", playing a classmate of narrator Kevin Arnold (Fred Savage). A guest stint on the ABC drama "My So-Called Life" and a supporting role in the "CBS Schoolbreak Special" presentation "Between Mother and Daughter" added more credits to Sloane's resume while keeping her in the public eye.
A regular role on the short-lived NBC sitcom "Mr. Rhodes" (1996-97) was followed by a regular part on the ABC sitcom "Sabrina, the Teenage Witch". Here Sloane was afforded her most visible role to that point, playing the eponymous high schooler's naive but spirited friend Valerie. She played the mermaid Fin in the spin-off TV-movie "Sabrina Down Under" (ABC, 1999), and reteamed with former ABC co-star Fred Savage, guesting on an episode of the actor's series "Working" (NBC) in 1998. Sloane was subsequently featured with a 1999-2000 two-episode recurring role on Fox's "That '70s Show" and a guest turns on the NBC series "The West Wing" and "M.Y.O.B." in 2000. Later that year she was cast as insecure and amiable actress Marcy Sternfeld on the teen-drama spoofing sitcom "Grosse Pointe" (The WB). Said to be playing the cast member based on Tori Spelling in the "Beverly Hills, 90210"-like series-within-a-series, Sloane's character underwent some changes in order to not strain relations between Aaron Spelling and producer Darren Star. A young and cute but oddly unpopular actress with an eating disorder and very low self-esteem, Marcy was the most likeable character on the show, and Sloane's charming girl-next-door persona was a perfect fit for the guileless primetime soap actress.
While "Grosse Point" only lasted one season, Sloane quickly picked up film roles after the show ended in 2001. She appeared in "Man's Best Friend" in 2002 and was cast in the remake of the 1979 comedy "The In-Laws" (2003).