Attorneys for Renzi, who served in Congress from 2003 to 2009, said they were "disappointed by every guilty verdict" that concluded his prosecution, which began with his indictment in February 2008.
Renzi, who was convicted on his 55th birthday, was charged with racketeering, conspiracy, money laundering, extortion, making criminal transactions, making illegal campaign contributions and insurance fraud, NBC said.
The indictment alleged Renzi concealed his involvement in land deals involving two companies and used his position on the House Natural Resources Committee to grease the wheels.
He was also accused of stealing insurance clients' premiums to help finance his 2002 congressional campaign.
A business associate, James W. Sandlin, also was convicted.
The Arizona Republic reported Renzi will remain free pending sentencing Aug. 19.
The newspaper said Renzi had no comment as he left the courthouse.
"We are pleased that the jury acquitted Mr. Renzi on 15 counts," defense co-counsel Kelly Kramer said in a statement released later. "We are disappointed by every guilty verdict. We will continue to fight these charges, including on appeal."
Acting Assistant U.S. Attorney General Mythili Raman said in a statement after the jury's decision Renzi's "streak of criminal activity was a betrayal of the public trust and abuse of the political process."