New York (CNN) -- The son of actor Michael Douglas apologized to a federal judge before being sentenced to a five-year prison term Tuesday, promising to follow "the true right path" when released.

Cameron Douglas, 31, pleaded guilty to distributing large quantities of methamphetamine and cocaine in January.

"I apologize to the court for my decisions and actions that put me in front of you today," Douglas said in a trembling voice. He added, "I have developed, in my mind, the idea that I want to take the right path, the true right path."

U.S. District Judge Richard Berman rebuffed pleas by defense lawyers for a more lenient sentencing, telling the spectators that prison may be Douglas' "last chance."

Cameron Douglas is the son of the two-time Academy Award winner and his first wife, Diandra Luker, both of whom attended the sentencing. As Cameron Douglas spoke, his mother was crying and his father appeared to be fighting back tears.

Douglas, who was arrested in July 2009 at a Manhattan nightclub, asked Berman "for opportunity to be a role model to my younger brothers and sisters."

"I believe, your honor, things will be different this time," he added. If given a second chance, he said, "I will never squander that opportunity."

Berman acknowledged that numerous letters sent on the defendant's behalf by celebrities and others, but said some of the letters implied that he should not make an example of Douglas because he is the son of a famous actor.

"None acknowledged appropriately the numerous impacts to victims of society for dealing drugs," the judge said.