Stokes was born at Skreen (now in the Republic of Ireland) and studied at Cambridge, remaining there throughout his life. In 1849 he became Lucasian Professor of Mathematics, but he found it necessary to supplement his slender income from this post by teaching at the Government School of Mines in London. He held his Cambridge chair until his death aged 84. He was the member of parliament for the university and among his many honors were a baronetcy conferred on him in 1889.

Stokes was equally interested in the theoretical and experimental sides of physics and did important work in a wide area of fields, including hydrodynamics, elasticity, and the diffraction of light. In hydrodynamics he derived the formula now known as Stokes's law, giving the force resisting motion of a spherical body through a viscous fluid. Among Stokes's other fields of study was fluorescence – one of his experimental discoveries was the transparency of quartz to ultraviolet light. He was also much interested in the then influential concept of the ether as an explanation of the propagation of light. Stokes became aware of some inherent difficulties with the concept, but rather than rejecting the whole idea of an ether he tried to explain these problems away by using work he had done on elastic solids, though naturally enough problems arose with his own ideas.

Stokes was perceptive in his views of other physicists' work. For example, he was among the first to appreciate the importance of the work of James Joule and to see the true meaning of the spectral lines discovered by Joseph von Fraunhofer.