Nine-year-old Joseph Marsh’s big dreams of acting became reality when he appeared on Wednesday’s popular police drama “Criminal Minds.”

The third-grader at White Bluffs Elementary School in Richland played Billy Young, an 8-year-old boy on the CBS show.

The Richland boy’s real 13-year-old sister Katie also is an actress and the reason he’s pursuing acting gigs.

Katie was up for a small part in the 2010 movie “Extraordinary Measures,” starring Harrison Ford and Brendan Fraser. When Lisa asked Joseph if he was interested in acting in it, he jumped at the chance.

“So I submitted him online and two weeks later he was offered the part to be a sick kid in a hospital bed,” his mother said. “After that, he said, ‘I was only here for two days — I wanted to be in the whole movie!’ ”

“It was good,” Joseph said of the experience. “I like to meet famous people.”

Last year, Lisa took him to L.A. for acting lessons and he spent most of the summer with private coach Vicki Baumann. After performing a scene for Scott David, a casting director for Criminal Minds, Joseph was called to audition for the show.

“I think they thought we lived in L.A.,” his mother said. “So we booked a flight the next day. The audition was in a couple days.”

Allowing her son to play a young boy being pursued by a serial killer was unsettling to his mother, but after meeting the other children on set, Lisa said she realized these kids want to be there.

“I thought, ‘God, what am I doing?’ ” she said. “But none of them were nervous at all. Joseph stepped right up to the plate.”