Expect a change in tone and style but not in direction from Jesse Sharkey, newly named acting president of the Chicago Teachers Union.

The union's vice president and No. 2 leader is filling in for President Karen Lewis while she recovers from surgery and upcoming chemotherapy for a cancerous brain tumor, which also took her out of the running for mayor.

From the bargaining table to the picket line, he's been at her side as a strategic adviser, internal troubleshooter and the policy wonk behind her free-wheeling, sharp-tongued commentary.

“She often jokingly calls me her work husband,” said Mr. Sharkey, a native of rural Maine who lives in Rogers Park with his wife and two children, who attend Chicago public elementary schools. “I stand behind her in a suit and crack up at her jokes, (allowing) her to be expressive and talk in classic Karen style.”

Ms. Lewis, 61, and Mr. Sharkey, 44, have been close allies from the beginning when they organized a slate of rank-and-file teachers in 2009 to replace the union's longtime leadership, promising a more vigorous pushback against charter schools and other reforms coming out of City Hall. She was a chemistry teacher at Martin Luther King College Prep, and he was a social studies teacher at Senn High School.

He takes the helm at a time when contract negotiations are starting soon and expected to come to a head next year, along with a mayoral election in February in which the union is still likely to do all it can to topple Mayor Rahm Emanuel. There's also the fight for an elected school board and against pension cutbacks.

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