He articled in law with Sir Frederick Barker, was called to the bar in 1893 and set up practice in Saint John.

Tilley was elected to the provincial legislature in 1916 as a Conservative MLA and became a cabinet minister in 1925 under Premier John B. M. Baxter.

During the federal Liberal-Conservative Party's 1927 national convention in Winnipeg, Tilley was chosen to nominate R. B. Bennett as one of six leadership candidates.

Tilley's endorsement of Bennett was blunt and prescient: "I nominate a gentleman whom, I believe, will be a winner."

Tilley died in Saint John, New Brunswick, Canada at the age of 77.