He was elected to the Faculty of Advocates in 1685, and was a Commissioner to the Parliament of Scotland for Cullen, Banffshire from 1681 to 1682 and from 1689 to 1695.

Although in the Convention Parliament of 1689 he had spoken for James VII, he took the oath of allegiance to William and Mary, and after filling some minor official positions he was appointed to senior roles.

[1] Upon his royal appointment as Secretary of State in 1696 he relinquished his representation of Cullen and continued in parliament instead by right of his office.

He served as first Lord Chief Baron of the Scottish Court of Exchequer, established by the Act of Union.

Findlater was admitted to the Privy Council of Great Britain in 1707 and was appointed Lord Chief Baron in the Court of Exchequer in 1707.