In 1848, Low and his eldest son Sampson Jr. opened a publishing office at the corner of Red Lion Court, Fleet Street.

The firm removed in 1867 to 188 Fleet Street, in 1887 to St. Dunstan's House, Fetter Lane, and subsequently to Paternoster Row.

It also published the photographic work of Polish Count Stanisław Julian Ostroróg, known professionally as Walery Ltd., as "Celebrity Portraits" by Sampson Low & Co. in the late 1880s.

With his son, he was instrumental in establishing in 1843 the Royal Society for the Protection of Life from Fire, and gave it careful attendance till 1867, when it was taken over by the Metropolitan Board of Works.

In about 1844, he made the acquaintance of Fletcher Harper of New York, and became his literary agent and correspondent, and one of the chief American booksellers in London.

Of his sons, Sampson Low, Jr., born in London on 6 July 1822, although an invalid, took a considerable share in the business.

He compiled a work entitled The Charities of London, comprehending the Benevolent, Educational, and Religious Institutions, their Origin and Design, Progress, and Present Position, 1850, of which corrected editions appeared in 1854, 1862, 1863, and 1870.