tread the boards

From the fact that theatre stages are often made of wooden boards which are trodden by actors. Compare French monter sur les planches (literally “to get up onto the boards”). The term boards (“a theatrical stage”) was first attested in the mid-1700s, this idiom itself was first attested in the mid-1800s, and was preceded by the idiom tread the stage, first attested in 1691.

• "He seems to think that he's the greatest actor who's ever trod the boards."
• "[…] I vvent, on the follovving morning, to the theatre to rehearſe; and my ignorance of ſome ſtage cuſtoms, vvhen I arrived there, vvas eaſily conſtrued into my confuſion, at rehearſing in a ſtrange company, vvhich any one vvho has ever trodden the boards, knovvs to be a much more formidable ordeal, than the actual performance at night; […]"
• "How do I know she would have succeeded? She had never then trod the boards. Besides, what strikes you as so good in a village show, may be poor enough in a metropolitan theatre."
• "The sleek bigot of the conventicle is a more superb actor than the applauded mime who treads the boards."
• "This actress was an amiable woman; and Madge enacted Celia in "As You Like It" at her benefit without any revival of the dread of Shakspeare [i.e., William Shakespeare] which the tragedian had implanted in her. She was now beginning to tread the boards with familiar ease. At first, the necessity of falling punctually into prearranged positions on the stage, and of making her exits and entrances at prescribed sides, had so preoccupied her that all freedom of attention or identification of herself with the character she represented had been impossible."
• "Jack and Stephen, treading the boards together in Dublin, could not be summoned so fast."
• "As Mac Wellman's Crowbar so powerfully suggests, every performance, like every theatre building, is haunted by what has come before, by the ghosts of characters and actors who have trod the boards."
• "He spent eight years before the war treading the boards as a professional actor in repertory theaters in Manchester."
• "Low comedy. Not fit for a thespian like me. If you want burletta, go to a saloon. I, sir, am Sir Theodore Cannon, and have treaded the boards with Booth, and with Bartlett."
• "After years of acting, she decided to tread the boards as a playwright instead, penning three successful comedies for the local theater company."

• tread the stage
• walk the boards

• as ever trod shoe-leather
• on board