Aislabie's family were originally Baltic merchants who settled in York. His father George married into the highly influential Mallory family. He attended St. John's College and Trinity Hall at Cambridge. He inherited the Studley estate from his mother's family in 1693, and started serious development of the garden around 1716, becoming the first in England to introduce natural landscaping. (His son William added the ruins of Fountains Abbey to the estate.)
Aislabie was elected as a Member of Parliament for Ripon in 1695, apparently on the assumption he was a Tory, though his political views were somewhat fluid. He became more active in politics from 1704, especially on the economy. He eventually became associated with the Country Whigs. Under the patronage of Robert Harley he was appointed a Lord of the Admiralty from 1710 in the Tory administration. This proved a precarious appointment as Aislabie's Whig sympathies manifested in votes against the government.
When the Whigs returned to office in 1714, Aislabie was made Treasurer of the Navy. He became an ally of the Earl of Sunderland who became, in effect, Prime Minister in 1718. Sunderland appointed Aislablie as Chancellor of the Exchequer. 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.
The South Sea Company had been built on high expectations which it could never fulfil, and it collapsed in August 1720. An investigation by Parliament found that Aislabie had been given £20,000 of company stock in exchange for his promotion of the scheme. He resigned the Exchequer in January 1721, and in March was found guilty by the Commons of the "most notorious, dangerous and infamous corruption". He was expelled from the House, removed from the Privy Council, and imprisoned in the Tower of London.
After his release from prison, he retired to his estate and continued the development of the gardens.
The obelisk in Ripon's Market Square, the first in England, was provided by John Aislabie in 1702.
Charles Mackay, Extraordinary Popular Delusions and the Madness of Crowds available from Project Gutenberg