Lawyer and politician.
Fled Scotland after the defeat of the Jacobites and settled in New Jersey. Appointed surveyor general (1715). New Jersey attorney general (1723-27).
Also held appointed positions in New York. With William Smith, he served as counsel for John Peter Zenger until dismissed for contempt.
A founding member of the American Philosophical Society, Alexander was interested in mathematics and science.
Born in Scotland. Married c. 1715 to — Provoost, a widow; five children, including William Alexander (Lord Stirling).