Yahya Farooq Mohammad, 39, admitted to conspiring with three associates to provide $22,000, equipment and "other assistance" to Al-Awlaki in 2009 "to support violent jihad" against US troops in Iraq, Afghanistan and elsewhere, according to a Justice Department press release
He pleaded guilty to one count of solicitation to a crime of violence in relation to the judge and one count of conspiracy to provide material support to terrorists.
Prosecutors say Mohammad traveled to Yemen in 2009 to deliver the money he had raised to Al-Awlaki, but ultimately couldn't meet up, so Mohammad gave it to a courier instead.
Al-Awlaki -- a US-born cleric
who was suspected of directing the plot to blow up a flight over Detroit in 2009 -- was later named a specially designated global terrorist before he was killed in a drone strike in 2011.
"The defendant conspired to provide and did provide material support to Anwar Al-Awlaki in response to his calls to support violent jihad," acting Assistant Attorney General Dana Boente said in a statement. "The National Security Division's highest priority is counterterrorism and we will continue to pursue justice against those who seek to provide material support to terrorists."
After Mohammad's arrest, prosecutors say he tried to coax an undercover FBI agent posing as a "hitman" in jail to kidnap and murder US District Judge Jack Zouhary, who was then presiding over his case in Ohio.
Mohammad allegedly told another inmate in jail that he was willing to pay as much as $15,000 to carry out the plot. And when later asked by the FBI agent when exactly he wanted the judge killed, Mohammad allegedly said, "The sooner would be good, you know," according to prosecutors.
"Conspiring to have a judge killed is not the way to avoid being prosecuted -- now Mohammad will be held accountable for additional serious federal charges," Special Agent in Charge Stephen D. Anthony of the FBI's Cleveland field division said in the DOJ statement.
But Mohammad's defense attorney, Thomas Durkin, said in an interview with CNN that "the government knows full well that it had significant evidentiary problems in this case."
Under the terms of Mohammad's plea agreement, he is expected face a little over 27 years in prison -- a "long way" from the life sentence that could have been imposed under the sentencing guidelines given the nature of the charges, Durkin said.
A sentencing date has not been set yet.