He was born at 1 Bath Place, New Road, London, on 19 March 1797, and, after being educated at Mr. Lord's school at Tooting in Surrey, attended in his father's manufactory, where he made himself master of practical engineering, and became a skilled draughtsman.

In 1822 he made the donkey engine,[citation needed] and in 1823 cast the statue of the Duke of Kent by sculptor Sebastian Gahagan that was erected in Park Crescent at the northern end of Portland Place in London.

At this time Braithwaite manufactured the first practical steam fire engine,[2] which was ultimately destroyed by a London mob.

1834 also saw Braithwaite plan and lay out the Eastern Counties Railway (ECR) in conjunction with Charles Blacker Vignoles.

Braithwaite was joint founder of the Railway Times, which he started with Joseph Clinton Robertson as editor in 1837, and he continued sole proprietor till 1845.

[3] Braithwaite had, in 1844, a share in a patent for extracting oil from bituminous shale, and works were erected near Weymouth which, but for his difficulties, might have been successful.

The experiment was abandoned on account of the deficiency of water in the canals and the completion of the railway system, which diverted the paying traffic.

From that year he was principally engaged in chamber practice, and acted as consulting engineer, advising on most of the important mechanical questions of the day for patents and other purposes.

John died suddenly at 8 Clifton Gardens, Paddington, on 25 September 1870, and his remains were interred in Kensal Green Cemetery.