The announcement comes just days after he angered his fellow Republicans by refusing to impeach Homeland Security Secretary Alejandro Mayorkas.
A House impeachment vote Tuesday fell just one vote short.
Gallagher did not mention the impeachment vote in a statement announcing his retirement, saying only that he doesn't want to grow old in Washington.
He spent last year leading a new House committee dedicated to countering China.
Gallagher was one of the highest-profile Republicans considering a run for U.S. Senate this year against incumbent Wisconsin Democrat Tammy Baldwin.
Persons:
Mike Gallagher, Alejandro Mayorkas, Mayorkas, Biden, Gallagher, Donald Trump, Joe Biden, ” Gallagher, ”, weren’t, Wisconsin Democrat Tammy Baldwin
Organizations:
— U.S . Rep, Homeland, GOP, GOP . Wisconsin Republicans, Milwaukee Journal Sentinel, Associated Press, Marine, U.S, Senate, Wisconsin Democrat
Locations:
MADISON, Wis, U.S, Mexico, Washington, “, Washington and Wisconsin, Green Bay, Wisconsin, China, Taiwan