Recent studies of temperature-responsive polymers, such as poly(N-isopropyl acrylamide) (PNIPAM), have revealed opportunities to utilise the smart materials to enhance the flotation recovery of valuable fines. PNIPAM undergoes a hydrophilic-to-hydrophobic transition when heated above a lower critical transition temperature (LCST), acting as a flocculant and collector. This study investigates the effect of shear and temperature on the flotation behaviour of a xanthate-functional temperature-responsive polymer, P(NIPAM-co-ethyl xanthate methacrylate (EXMA)), in the recovery of copper sulfide from a natural mixed-mineral ore. The results were compared with a conventional xanthate collector, potassium amyl xanthate (PAX). In a high-shear mechanical cell, P(NIPAM-co-EXMA) improved coarse grades and fine recoveries upon heating above the LCST, through the aggregation of valuable fines into larger sizes more amenable to flotation, while limiting hydrophobic slimes coating on gangue particles. Flotation using the polymer in a column cell produced little improvement relative to PAX, despite the formation of larger particle aggregates under reduced shear. P(NIPAM-co-EXMA) behaved as a sulfide depressant at temperatures below the LCST, where it renders the surface hydrophilic, displaying tuneable collector/depressant properties. Addition of polymer to suspension above the LCST improved concentrate grades, attributed to enhanced selectivity relative to addition below the LCST prior to heating.