His television roles[9] include Clarence in The Hollow Crown (Henry IV Parts I and II), Ottaviano Riario in Borgia.
In 2017 Tennyson played the title role in the Royal Shakespeare Company's gender-fluid 2017 production of Oscar Wilde's Salomé.
[10][11] He is a frequent collaborator with the playwright Robert Holman since appearing in the Donmar Warehouse production of his play Making Noise Quietly.
Tennyson played the war poet Wilfred Owen in Terence Davies film biopic of Siegfried Sassoon, Benediction.
In 2023, it was announced that Tennyson would be joining the cast of The Pillowman by Martin McDonagh at The Duke of York's Theatre from June 2023.