Loughlin, accompanied by husband Mossimo Giannulli, arrived near the courthouse in a black van, exiting from one of the back passenger doors.
She then walked across a plaza outside the courthouse, surrounded by a slew of reporters, protesters, and fans, pausing only to sign a few autographs.
While some shouted phrases of support, such as "I love you, Lori!" others jeered, yelling "Lori, pay my tuition!"
After waiting in the front row in the courtroom for about 40 minutes, Loughlin and Giannulli were brought before the judge. They said they understood their rights and the charges and waived their rights to preliminary hearings in the case.
Soon, they exited the courthouse and left the area.
Loughlin and Giannulli are among the 33 parents facing charges in a nationwide college bribery scheme. Federal prosecutors announced the indictments on March 12. Loughlin and Giannulli were charged with conspiracy to commit mail and honest services fraud. They face up to 20 years in prison each if convicted.
Prosecutors said that the couple paid William "Rick" Singer, who ran a nonprofit called The Key Worldwide, also known as The Edge Career Network, $500,000 to get their daughters designated as recruits for the University of Southern California's rowing team.
Olivia Jade, 19, and Isabella, 20, both got into the school under the guise of being athletic recruits despite never having competed at a competitive level.
Isabella, an actress, also reportedly didn't want to attend school.
Singer pleaded guilty on March 12 to racketeering conspiracy, money laundering conspiracy, conspiracy to defraud the United States, and obstruction of justice; prosecutors said he cooperated with federal law enforcement for months, calling the parents embroiled in the scheme and recording conversations to get officials more evidence to support the indictments.
Singer is due to be sentenced in June and was released on $500,000 bond.