John Sparrow David Thompson

Sir John Sparrow David Thompson (November 10, 1845 – December 12, 1894) was the fourth prime minister of Canada, serving from 1892 until his death in 1894. He had previously been fifth premier of Nova Scotia for a brief period in 1882. He is the only post-Confederation provincial premier to become prime minister, as of 2026.

Thompson was born in Halifax, Nova Scotia. He trained as a lawyer and was called to the bar in 1865. Thompson was elected to the Nova Scotia House of Assembly in 1877 as a representative of the Conservative Party. He became the provincial attorney general the following year, in Simon Holmes's government, and replaced Holmes as premier in 1882. However, he served for only two months before losing the 1882 general election to the Liberal Party. After losing the premiership, he accepted an appointment to the Nova Scotia Supreme Court.

In 1885, Thompson entered federal politics at the personal request of Prime Minister John A. Macdonald, becoming Minister of Justice. In that role he was the driving force behind the enactment of the Criminal Code. Thompson became prime minister in 1892, following the retirement of John Abbott. He was the first Roman Catholic to hold the position. On a trip to England in 1894, Thompson unexpectedly suffered a heart attack and died, aged 49. He is only the second Canadian prime minister to have died in office, after John A. Macdonald.