In 1852 he became an engineer for the Magnetic Telegraph Company, for which he laid thousands of miles of underground telegraph lines in England as well as the first undersea cable (1853) from Portpatrick, Scot., to Donaghadee, Ire. In 1856, Bright, with Cyrus Field and J.W. Brett, formed the Atlantic Telegraph Company, whose purpose was to lay the first Atlantic cable between Ireland and Newfoundland. Bright was made engineer in chief. After two failures, Bright landed the Irish end of the line at Valentia, County Kerry, in August 1858. A few days later he was knighted in Dublin. Although the cable broke down in October, its success had proved the practicability of the scheme. He was consulting engineer for the second and third Atlantic cables (cable) of 1865 and 1866. Subsequently, he supervised the laying of submarine cables in several other regions.

With Joseph Latimer Clark, he invented an asphalt-composition insulation for submarine cables. A paper on electrical standards read by them in 1861 before the British Association for the Advancement of Science led to the establishment of a committee whose work founded the system still in use. From 1865 to 1868 Bright was Liberal member of Parliament for Greenwich.