Apprenticed to the banking house of William Pepys & Co. he later became a partner in the firm of Vere and Asgill, bankers of Lombard Street, in the City of London, in 1740.

[5] Asgill was Alderman of Candlewick Ward (1749–1771) and was also Master of the Skinners Company (1749), a Governor of Bridewell Royal Hospital (1743–1750), where his friend, the banker Sir Richard Glyn, was President.

His resentment of the attitude of King and Ministry towards the American Colonies amounted to a passion; and he refused a peerage offered him, it was said, in the hope of shifting his influence.

Sparkling with energy and imagination and noted for her charm, she shared her husband's humanitarian and political ideas; and the two enjoyed as household friends some of the first Whig lights of the day— statesmen, publicists, men of letters".

[16] His obituary in the Gentleman's Magazine stated that "he was a strong instance of what may be effected even by moderate abilities, when united with strict integrity, industry and irreproachable character.

Asgill and his wife Sarah also had five daughters; only two, (Amelia Angelina Colvile and Caroline Augusta Legge) still living at the time of the death of his widow on 6 June 1816.

[20][21] Due to the fact that the British were forced to introduce controversial legislation for the colonies, in an attempt to remedy the crisis, this then became one of the causes of the American Revolutionary War.