Henry Isaacs was a leading City trader, and, as a Liberal aged 32, he was elected as a Common Councillor in 1862 in the Aldgate ward.
A Freemason, he was Master of the Worshipful Company of Loriners, Warden of the Hambro Synagogue, a member of the Jewish Board of Guardians and a Justice of the Peace (J.P.) for London.
He agitated for improving the dwellings of the poor, and was mainly instrumental in bringing about much-needed reforms in the finance committee of the corporation.
Some years later, as head of the Markets Committee, he gave valuable evidence before the House of Commons; and Tower Bridge owed its existence, in a great measure, to his persistence.
Favouring the oral system of teaching deaf-mutes, his brochure Sounds Versus Signs was a recognized authority.