​Marcasiano is the president of her eponymous design company in New York City.
​She has designed clothing and accessories, under her own brand and for other prestigious fashion companies since 1978. Marcasiano is a graduate of the Parsons School of Design/The New School and the recipient of the Cartier, DuPont, Cutty Sark and Wool Knit Awards and a member of the CFDA since 1979. Marcasiano has licensed her designs to Ben Kahn Furs, Italo Colombo shoes, Otto Grun Jewelry and been a design consultant for Joan Vass, Cole Haan, Malo Tricot and Saks Fifth Avenue.