Republican Ralph Hall, of Texas, who recently switched parties, filled GOP vacancies on the Energy and Commerce, International Relations and Science Committees.
As a Democrat, Hall was member of the Energy & Commerce and Science committees.
Rep. John Sullivan, R-Okla., was named to the Energy and Commerce Committee, as was Rep. Sue Myrick, R-N.C.
Myrick, the speaker's office said, would immediately go on leave so that she could continue to serve as a member of the House Rules Committee.
Missouri's Rep. Roy Blunt, the House majority whip, is also taking a leave from the Energy and Commerce Committee and will assume new duties as a member of the International Relations Committee.
"Each of these members has an exceptional background and a remarkable knowledge of the issues," said Hastert. "I congratulate each of them and look forward to working with them in their new roles."