Carona must now report to prison on July 24, although Guilford left a window for his attorneys to take the matter up with the 9th U.S. Circuit Court of Appeal.
Carona's attorneys, Jeff Rawitz and John Cline, did not immediately return calls for comment.
Carona once led the nation's fifth-largest sheriff's department. He was indicted on six felonies, including conspiracy, witness tampering and mail fraud, in a sweeping public corruption case. Federal investigators spent five years building the case, which stretched back to the three-term sheriff's first run for office in 1998.
But a jury acquitted Carona in January of all but one witness-tampering count.
Assistant U.S. Attorney Ken Julian declined to comment.