Alexander Coosemans was a Flemish Baroque painter specialized in still lifes of flower pieces, fruit, and inanimate subjects. He painted vanitas still lifes, pronkstillevens and game pieces.

Very little is known about the life of Coosemans. He was born in Antwerp where he was baptized on 18 March 1627. His father was a carpenter from Brussels who had become a poorter of Antwerp in 1617. His mother was Geertruid Beeck. His father had a successful cloth trading business and could afford to send his son to a good teacher.

Coosemans became a pupil of Jan Davidsz de Heem, the leading still life painter in the Netherlands, in 1641. He became a master in the Guild of St. Luke of Antwerp in 1645.

He was in Italy between 1649 and 1651. Here he worked on commissions for the Doria-Pamphili-Landi and reportedly contributed still life elements of fruit and flowers for decorative paintings by Pasquale Chiesa in the Palazzo del Principe (also called 'villa di Andrea Doria') in Genoa and the Palazzo Doria Pamphilj in Rome.

Coosemans returned to Antwerp in 1651. He remained a bachelor and is believed to have resided in Antwerp until his death on 28 October 1689.