[Fifty people were charged in the widespread scam to get undeserving students into colleges.]

One method involved bribing university officials to pass off applicants as athletic recruits even if they weren’t; the other used brazen cheating on standardized exams. And both schemes had Hollywood stars playing a role.

Ms. Huffman’s career in Hollywood stretches back to the 1970s. Her performance as Bree, the transgender main character in “Transamerica,” earned her an Oscar nomination in 2006. But much of her work has been in television. She is best known for roles including Lynette Scavo in “Desperate Housewives” and Dana Whitaker in the Aaron Sorkin show “Sports Night” as well as for several roles in the ABC show “American Crime.” Most recently, Ms. Huffman, 56, played Special Agent Clara Dillard in Epix’s “Get Shorty.”

In 1997, she married Mr. Macy, the same year he was nominated for an Oscar, after he starred in “Fargo.” Mr. Macy, 68, a veteran of many movies, currently plays Frank Gallagher, the head of the dysfunctional family in the Showtime comedy series “Shameless.” They have two daughters: The elder was born in 2000, and the younger two years later.

According to the authorities, William Singer, the head of a college preparatory business and the founder of the charity, met with Ms. Huffman and Mr. Macy in their Los Angeles home and explained how he could help them. Mr. Singer, who has pleaded guilty and is cooperating with investigators — he is identified as “cooperating witness 1” in the Justice Department complaint — said he could arrange for their daughter’s SAT proctor to secretly correct her wrong answers and boost her score. “CW-1 has advised investigators that Huffman and her spouse agreed to the plan,” the complaint said.