In the same year, he established a trading company, Boustead & Co.[1] Boustead & Co specialised in import and export, offering goods such as banca tin, spices, saps, rattan, medicinal herbs, silk and tea widely available in South East Asia in exchange for Western products like cloth, oil and machinery.

Boustead commissioned Irish civil architect, George Drumgoole Coleman to design his company's headquarters alongside the Singapore River.

Import of Western commodities such as textiles and machinery had to be balanced with exports of Eastern produce such as copra, coconut, pepper and tapioca.

Brokers and sellers could draw a specific percentage of advances against the value of their goods stored in the Boustead warehouse.

In 1892 Boustead & Co handled the first shipment of bulk oil to Penang and shortly after this the Shell Transport and Trading Company was formed with Isaac Henderson acting as one of its original directors.

Boustead & Co played a leading role as promoter and investor in the tin smelting facility on Pulau Brani, constructed by the Straits Trading Company.

Some of the famous brand names that became synonymous with Boustead were Cadbury's, Nestle, Del Monte, Gillette, Procter & Gamble, Johnnie Walker, Hennessy, Moet & Chandon, Nissan, Suzuki and Thomas Cook.

An enterprising businessman in the trading sector, Boustead was one of the founding members of the Singapore Chamber of Commerce in 1837.

He started the Horticultural Society, which supported the cultivation of pepper, cotton, sugar and other tropical produce.

Edward Boustead's house, designed and built by George Drumgoole Coleman, was one of the exclusive villas on Singapore's Esplanade.

In 2014 Boustead & Co co-founded Noble Tree Property Investment, a socially minded property company that develops, owns, lets and sells affordable housing and specialty supported housing developments across the United Kingdom.

The asset manager and fund are regulated by the Financial Services Commission in Mauritius and were granted a Collective Investment Scheme Manager Licence and Category 1 Global Business Licence by the Financial Services Commission.

William Edward Graham Niven then married socialite Henrietta Julia Degacher.