In making the announcement, Beadles said he will now serve as a co-chairman in the Harmer for Congress campaign.
Earlier, another 11th District candidate, Larry Pegram, withdrew from the race after Harmer announced his candidacy.
"David Harmer is a man of integrity and principle, and I believe he will win this seat for Republicans," Beadles said in a statement. "There's little doubt that our country faces an important crossroads; the 2010 elections will be among the most important in the past half century. Republicans everywhere should join me in supporting David Harmer so we can put our strongest candidate forward in the contest against Jerry McNerney."
U.S. Rep. McNerney (D-Pleasanton) is running unopposed on the June 8 primary's Democratic Party ticket for re-election to a third term in Congress.
Beadles joins Mitt Romney, the Howard Jarvis Taxpayers Association, National Tax Limitation Committee, 2008 nominee Dean Andal and others in supporting Harmer.
Harmer is campaigning as a lifelong Reagan Republican. His father, John Harmer, served as California's Lieutenant Governor under Ronald Reagan. Early in his career, David Harmer represented the Pacific Legal Foundation, where he defended property rights and other issues in state and federal courts. He was also a Resident Fellow at the Heritage Foundation, and his book on education reform was published by the Cato Institute, a market-oriented public policy organization.