TV Line reports that the actress will appear in at least six episodes of the show's seventh season.
She is expected to play Maxeen, a conceptual artist living in New York. She will also be a love interest for Andy Botwin (Justin Kirk).
Sloane has previously appeared in shows including The Wonder Years, Sabrina The Teenage Witch and Grosse Pointe.
More recently, she has worked on Funny or Die Presents... and has had guest roles in series like How I Met Your Mother, Mr Sunshine and The League.
Weeds was renewed in September and its seventh season is scheduled to premiere on June 27. The show's executive producer Jenji Kohan has previously admitted that she expects the seventh run to be the show's last.