[6] Bragg was the director of the Cavendish Laboratory, Cambridge, when the discovery of the structure of DNA was reported by James D. Watson and Francis Crick in February 1953.

Bragg was born in Adelaide, South Australia to Sir William Henry Bragg (1862–1942),[7] Elder Professor of Mathematics and Physics at the University of Adelaide, and Gwendoline (1869–1929), daughter of Sir Charles Todd, government astronomer of South Australia.

In the same year his father accepted the Cavendish chair of physics at the University of Leeds, and brought the family to England.

Bragg entered Trinity College, Cambridge in the autumn of 1909 and received a major scholarship in mathematics, despite taking the exam while in bed with pneumonia.

[11] In 1912, as a first-year research student at Cambridge, W. L. Bragg, while strolling by the river, had the insight that crystals made from parallel sheets of atoms would not diffract X-ray beams that struck their surface at most angles because X-rays deflected by collisions with atoms would be out of phase, cancelling one another out.

[12] Bragg was commissioned early in World War I in the Royal Horse Artillery as a second lieutenant of the Leicestershire battery.

After months of frustrating failure he and his group devised a hot wire air wave detector that solved the problem.

[24] After World War II, Bragg returned to Cambridge, splitting the Cavendish Laboratory into research groups.

[1][4] In 1919 when Ernest Rutherford, a long-time family friend, moved to Cambridge, Lawrence Bragg replaced him as Langworthy Professor of Physics at the Victoria University of Manchester.

He recruited an excellent faculty, including former sound rangers, but he believed that his knowledge of physics was weak and he had no classroom experience.

He and R. W. James measured the absolute energy of reflected X-rays, which validated a formula derived by C. G. Darwin before the war.

The Laboratory had an eminent history in atomic physics and some members were wary of a crystallographer, which Bragg surmounted by even-handed administration.

He showed Bragg X-ray diffraction data from haemoglobin, which suggested that the structure of giant biological molecules might be deciphered.

Bragg appointed Perutz as his research assistant and within a few months obtained additional support with a grant from the Rockefeller Foundation.

In 1947 he persuaded the Medical Research Council (MRC) to support what he described as the "gallant attempt"[27] to determine protein structure as the Laboratory of Molecular Biology, initially consisting of Perutz, John Kendrew and two assistants.

In 1953 the Braggs moved into the elegant flat for the Resident Professor in the Royal Institution in London, the position his father had occupied when he died.

He bolstered finances by enlisting corporate sponsors, the traditional Friday Evening Discourses were followed by a dinner party for the speaker and carefully selected possible patrons, more than 120 of them each year.

"[30] He also introduced a programme of highly regarded Schools' Lectures, enlivened by the elaborate demonstrations that were a hallmark of the Institution.

[31] He continued research in the Institution by recruiting a small group to work in the Davy-Faraday Laboratory in the basement and in the adjoining house, supported by grants he obtained.

This problem was solved by the development of another line Bragg had initiated, using modified electron microscopes to image single frozen molecules: cryo-electron microscopy.

Alice was on the staff at Withington Girls' School until Bragg was appointed director of the National Physical Laboratory in 1937.

Bragg's hobbies included drawing – family letters were illustrated with lively sketches – painting, literature and a lifelong interest in gardening.

He was buried in Trinity College, Cambridge; his son David is buried in the Parish of the Ascension Burial Ground in Cambridge, his grave is within a few paces of that of Bragg's close friend, Rudolph Cecil Hopkinson, who incurred a severe head wound in the 1914–19 war and died a few months after being invalided back to the UK.