Pisier has obtained many fundamental results in various parts of mathematical analysis. He is credited with transforming the area of operator spaces into a deep research area. In 1990s, he solved two extremely long-standing open problems. In the theory of C*-algebras, he solved, jointly with Marius Junge, the problem of uniqueness of C* norms on the tensor product of two copies of B (H), the bounded linear operators on a Hilbert space H. He and Junge were able to produce two such tensor norms that are nonequivalent. In 1997, he constructed an operator that was polynomially bounded but not similar to a contraction, answering a famous question of Paul Halmos.

1n 1997, Pisier received Ostrowski Prize for this work. He is also a recipient of Grands Prix de l'Academie des Sciences de Paris in 1992 and Salem Prize in 1979.

Pisier has authored several books and monographs in the field of functional analysis, harmonic analysis, and operator theory. Among them are:

• "The Volume of Convex Bodies and Banach Space Geometry", Cambridge University Press, 2nd ed., 1999. First published in 1989.
• "Introduction to Operator Space Theory", Cambridge University Press, 2003.
• "The Operator Hilbert Space OH, Complex Interpolation and Tensor Norms", Amer Mathematical Society, 1996.
• "Factorization of Linear Operators and Geometry of Banach Spaces", Amer Mathematical Society, 1986.
• "Similarity Problems and Completely Bounded Maps", Springer, 2nd ed., 2001. First published in 1995.
• "Random Fourier Series with Applications to Harmonic Analysis", with Michael B. Marcus, Princeton University Press, 1981.