LONDON — With his roaring cries of “Order! Order,” his antiquarian language and his constant needling of the government, John Bercow, the speaker of Britain’s House of Commons, became a celebrity of the Brexit era.

True to form, his announcement on Monday that he would leave his post and his seat in Parliament came wrapped with one final rebuke for Prime Minister Boris Johnson’s hard-line government. By timing his departure for the end of October, Mr. Bercow ensured that the current Parliament, packed with Johnson-averse lawmakers, would choose his successor.

That starved a future Parliament — perhaps one controlled by Mr. Johnson and purged of the Conservative rebels who defied him last week — from installing a more acquiescent speaker, one who would clear the government’s path to an abrupt Brexit. But it also left Mr. Bercow in place for long enough to preside over the electric run-up to the Oct. 31 Brexit deadline.

It was a fitting send-off for a speaker who galvanized so-called backbench members of Parliament, lawmakers who are usually consigned to following the orders of party leaders but, with Mr. Bercow’s help, have taken the reins at pivotal moments of the Brexit crisis.