In 1904 Hackney had a workforce of over 101,000. 65,000 of these were men, of whom approximately 10,000 worked in commercial industries, such as insurance, accountancy and banking. Improvements in transport meant that commuting to the City was becoming increasingly common. For women, particularly those that were not married, domestic service was still a big employer, although it declined dramatically during this period, from 1901-1939. For many women the independence of working in a factory was preferable to the long hours and hard graft that being in service offered, and there were increasing opportunities for factory work.

In 1904 Hackney had 1,229 factories and workshops. By 1938 this number had risen to 2,071, and the number of people they employed had risen from 17,714 to 46,333. Factories were more in the northern half of Hackney, around Dalston, Mare Street, Hackney Wick and the Lea, whereas workshops were predominantly in south Hackney, around Shoreditch, De Beauvoir and the canal.

These factories and workshops were producing the same goods that Hackney had already become renowned for. Half of the manufacturing workers, 23,000, in 1938 worked in the clothing or footwear industries, up from a third in 1904. Furniture and other wood based industries were also growing, accounting for a sixth of people working in manufacturing in 1938. In fact, in London as a whole the furniture industry rose by 75% during the 1920s and 30s to reach 65,000 employees by 1937.

Other Hackney industries in this period included paper and print, food, drink and tobacco. The tobacco business was already well established in Hackney. One company R & J Hill on Shoreditch High Street had been there since Georgian times and in 1907 won the sought after contract to supply the Royal Navy. They continued right through World War II despite losing the factory in the Blitz bombing of 1941.

One large employer whose premises survived the war was Simpson’s clothing company, who made 'DAKS' clothing and other ranges. They built a model factory on Stoke Newington Road, it was the most advanced clothing factory of the time, producing 11,000 garments a day at one point and employing 3,000 people. It is now the Halkevi Turkish Community Centre.

Amongst other companies of note was the Marconi Wireless Telegraph Company who were in Dalston on Tyssen Street from 1906. The company occupied the Shannon Factory, a very impressive building, now called Springfield House, that had been built in 1902 for a cabinet manufacturers. During the war the National Projectile Factory, a government factory made munitions near the Hackney Cut. Still on the waters edge, but further north, Latham's warehouse at Middlesex wharf was established in 1912. Latham's was a timber merchant who had moved from Liverpool to Shoreditch at the beginning of the 19th century.

In retail this period saw the emergence of national chains. Marks and Spencer had been in the borough since 1914, trading as the London Penny Bazaar. They took over Matthew Rose's department store on Mare Street in 1936. Also on Mare Street, Boots the chemists opened their first Hackney premises in 1911, W H Smith and Sons, on Stoke Newington High Street, in 1912, Woolworths in the same location in 1917. A national grocery chain, Home and Colonial Stores, were all over the borough by this time, having established themselves at the end of the Victorian period.

Agriculture had declined because of the spread of building, but also the withdrawal of Lammas rights in the Victorian period. Hackney marsh, which had been used for pasture was turned over to recreational use at the turn of the century. Worries about public health mean that beef and dairy farmers who had no land but kept their livestock in cowsheds were under increasing scrutiny and their numbers dwindled. There were still a few dairy farmers in Hackney in 1930, one in De Beauvoir and one in Upper Clapton.