No longer allowed
The court's ruling prevents the sheriff's office from carrying out some of Arpaio's policies that it said amounted to a violation of the Fourth Amendment, which protects against unreasonable search and seizure, and the Fourteenth, which guarantees equal protection under the law.
The MCSO will no longer be allowed to use race or Latino heritage to make any law enforcement decisions, including stopping vehicles, making detentions or holding suspects longer than necessary to resolve specific allegations.
The ruling is another slap from the federal justice system against Arizona's immigration policies.
The U.S. Supreme court in June 2012 struck down parts of the state's controversial immigration law, including provisions for law enforcement that were similar to those practiced by Arpaio, and which the court deemed unconstitutional.
Law enforcement veteran
Arpaio's office claims to be the third largest sheriff's office in the United States and boasts more than 3,400 employees.
Before becoming sheriff, Arpaio was a federal narcotics agent, who eventually headed the Arizona office of the Drug Enforcement Agency, according to his biography on the MCSO website.
In April, a postal inspector intercepted an explosive package addressed to him. It was mailed a day after the department received a death threat from a major drug cartel.
In a CNN interview before his trial began, Arpaio said his department would continue to pursue illegal immigrants.
"I know I'm doing the right thing. I'm not going to surrender by those little small groups, people that don't like what I'm doing. You think I'm going to surrender? It'll never happen," the sheriff said at the time.
But on Friday attorney Casey said "America's Toughest Sheriff" will comply with the court's ruling -- for now.