[citation needed] Cozens-Hardy acquired a large junior practice at the Chancery bar, and became Queen's Counsel in 1882.

[citation needed] In 1885, Cozens-Hardy was returned as the Liberal Member of Parliament for North Norfolk, keeping the seat until 1899.

He remained with Gladstone when the Liberal Party split over Irish Home Rule in 1886, although he wavered towards the defectors for a time.

In 1899, the elevation of Sir Robert Romer to the Court of Appeal on the death of Lord Justice Chitty created a vacancy in the Chancery Division.

Cozens-Hardy was duly appointed to the High Court and assigned to the Chancery Division, receiving the customary knighthood in the 1899 Birthday Honours.