[1] It was created in 1926 for Rufus Isaacs, who had been Member of Parliament for Reading between 1904 and 1913, before serving as Viceroy of India and Lord Chief Justice of England and Wales.

He notably held ministerial office from 1951 to 1957 in the Conservative administrations of Winston Churchill and Anthony Eden.

As of 2024,[update] the titles are held by his grandson, the fourth marquess, who succeeded his father in 1980.

In May 1804, the title of Baron Reading was offered to the outgoing prime minister, Henry Addington, who had many links with the largely pre-industrialised town, as a subsidiary title of the customary retirement earldom for prime ministers.

The heir apparent is the present holder's son, Julian Michael Rufus Isaacs, Viscount Erleigh (born 1986).