He was Chancellor of the Exchequer at the time of the South Sea Bubble and his involvement with the Company led to his resignation and disgrace.

He was the first in England to introduce natural landscaping and created the water garden at Studley Royal.

As mayor he was generous in paying for the reconstruction of the Market Cross, and making gifts to the corporation.

At the 1705 English general election, he was returned again for Ripon and voted for the Court candidate as speaker on 25 October 1705.

When in 1719 the South Sea Company proposed a deal whereby it would take over the national debt in exchange for government bonds, Aislabie was a very strong supporter of the scheme and negotiated the contract; he piloted the Bill through the House of Commons.

He resigned the Exchequer in January 1721, and in March was found guilty by the Commons of the "most notorious, dangerous and infamous corruption".