Sage Simone entered Parsons the New School for Design in 2009, majored in fashion design, and earned a Bachelor of Fine Arts in 2014. While at Parsons, she took special courses in knitting, shoe design and construction, accessory design and construction, and textiles. Outside the classroom, she was a finalist in the Banana Republic design competition for womenswear and accessories and placed second in the All Japan Fashion Teachers/Color Test Institute Fashion Illustration Competition.  

During Sage's junior year, she secured an internship at Dennis Basso, working directly under the creative director. As a full-fledged member of the design team, she rendered sketches, copied fur patterns, and shadowed fabric and embroidery meetings. Shortly before graduation, she was offered a permanent Assistant Designer position and was later promoted to a full Designer.

During her time at Dennis Basso, she was instrumental in moving the line to a more youthful, fashion-forward direction all while retaining the brand’s loyal customers. Her daily duties included researching each collection’s concepts, sketching, designing, choosing fabrics and embroideries, creating fur and fabric techniques, sourcing materials, assisting fittings, providing technical flats for patternmakers, and collaborating with outside embroidery, knitwear, and fur factories. As a result, Sage's fashion illustrations have been featured by The Cut, Pantone, The Observer, AOL, The Daily Mail, US Weekly, E! News, and People Magazine. Her pieces for the brand have also been featured in editorials from Womenswear Daily, the Luxury Art Book and Essence Magazine.