An American aide to the United Arab Emirates’ ambassador to the United States and head of his personal U.S. charity was sentenced to 21 months in prison Friday after admitting to misspending more than $1 million in foundation funds at casinos and adult entertainment businesses.

Byron K. Fogan, 43, of Columbia, Md., pleaded guilty in November in federal court in Washington to one count of money laundering as executive director of the Oasis Foundation of D.C. The foundation was established by UAE Ambassador Yousef al Otaiba in 2008 to work with the embassy and advance positive relations with his nation, which is a key U.S. ally in the Persian Gulf, court files state.

Through various channels, the UAE has given hundreds of millions of dollars to U.S. causes including recovery efforts from hurricanes Katrina and Sandy, as well as the Joplin, Mo., tornado.

Its gifts to U.S. hospitals, schools and ballfields have ranged across the country, including New York, Los Angeles and Miami, and include $150 million in 2009 to Children’s National Medical Center in Washington for a new pediatric surgery research center.

Yousef al Otaiba, United Arab Emirates ambassador to the United States, in Washington. His American aide, Byron K. Fogan, 43, was sentenced Friday to 21 months in prison. (2009 photo by Pablo Martinez Monsivais/Associated Press)

The UAE Embassy in Washington, where Otaiba has emerged as one of the capital’s most influential ambassadors, declined to comment.

In a letter to the court, the foundation’s current executive director spoke in support of ­Fogan.

Hamilton Loeb, an attorney with the Paul Hastings law firm who led Oasis after Fogan and who is counsel to the embassy and Oasis’s founder and sponsor, asked in their behalf as victims that Fogan receive leniency so that he could repay the funds.

“Mr. Fogan had a record of accomplishment, professionalism, reliability and loyalty prior to the events in this case,” Loeb wrote the court. “The interests of the Foundation will best be served by a sentence that gives him a chance to demonstrate that he can resume making positive contributions to the community.”

Fogan was a close friend of Otaiba since their undergraduate days at Georgetown University, Fogan’s attorney said in court papers. Fogan also has worked for the embassy and Otaiba as vice president at the Harbour Group public relations firm, as a registered U.S. agent, and as legal counsel through his personal law office.

Both sides said the amount misspent by Fogan from 2011 to 2013 while he enjoyed exclusive control of the foundation’s funds exceeded $1 million but was not precisely known. Fogan at one point transferred $7.4 million from the foundation to accounts under his control before spending some properly and repaying some money before he was caught by law enforcement, according to court files.

Loeb said in a statement after sentencing that Fogan’s conduct “had no impact” on Oasis-funded programs, and that the foundation disbursed $6 million and “fulfilled all of its obligations” related to programs, including a new neonatal unit at Joplin Mercy Hospital, child educational programs in Washington and Chicago, and a Baltimore homeless shelter.

Fogan said he sought to make amends and took “full responsibility” for his conduct, which he said occurred “while in the throes of a vicious gambling and alcohol addiction.”

“The consequences of my addictions are significant, and I am ashamed for the damage I have caused to my former employer, the community, my friends, and my family,” Fogan said in a written statement before sentencing by U.S. District Judge Rosemary M. Collyer.

Fogan’s attorney, Preston Burton,of the Poe & Burton law firm of Washington had asked that Fogan be spared prison and granted treatment or home confinement with a minimal fine. Fogan remains in contact with Otaiba and advises the embassy when requested, Burton wrote.

“What led to Mr. Fogan’s gambling and alcohol addiction and downward spiral is, of course, difficult for friends and colleagues to know and understand,” Loeb said. “He hid it successfully from those who were closest to him, until it was forced into the open by the investigation in this case.”

Federal prosecutors sought a 27-month prison sentence. ­Collyer imposed the shorter term and ordered restitution to the foundation of $223,569 in illegally laundered money traced in bank transactions in excess of $10,000.

“The total amount fraudulently obtained was not determined, in part due to the defendant’s early acceptance of responsibility,” Assistant U.S. Attorney Zia M. Faruqui of the District wrote in seeking prison time. “In a sense, the victims of the defendant’s conduct are . . . people whose lives could have been changed for the better, had the defendant not spent the charity’s funds on his personal vices.”