Pierre Theunis was born in Antwerp, 1st May 1883. He enrolled at the Academy of Fine Arts in Brussels, a city with a flourishing colony of artists, craftsmen and architects working in the Art Nouveau style. Theunis studied under the sculptor Thomas Jules Vincotte (1850-1925) professor at the academies in both Antwerp and Brussels. Vincotte was a sculptor of primarily portraiture and with an international reputation; he exhibited at the Royal Academy in London.

Following his studies Theunis set himself up as a sculptor of figurative and allegorical works using the medium of bronze and marble. He was, in addition a successful sculptor working in relief producing commemorative medals receiving commissions from commercial bodies, for example the Banque de Bruxelles and the state.

However, his work is seen at its finest in examples of his figurative marble sculptures featuring an elegance and sensitivity born of the Art Nouveau movement.

Pierre Theunis died in Brussels in 1950.

His works can be found in museums in: Brussels and Ghent.