She will play an experienced investigator from Washington whose work is driven by her empathy for the victim, the network said.
Ward is to make her first appearance in the show's Season 7 premiere this fall.
"We are delighted to have Sela joining 'CSI: NY,'" Executive Producer Pam Veasey said in a statement. "With the exciting stories planned for Season 7, she'll be a dynamic addition to the cast and the team."
"I am thrilled to be working with Gary (Sinise) and this terrific group of people," Ward added. "I'm a huge fan."
Ward won an Emmy Award for Outstanding Lead Actress in a Drama Series in 1994 and 2000 for her roles on "Sisters" and "Once and Again," also winning a Golden Globe Award for the latter role in 2001. Her other television credits include a recurring role on "House," and the telefilms "Suburban Madness" and "Almost Golden: The Jessica Savitch Story." Her film credits include "The Guardian," "The Day After Tomorrow" and "The Fugitive."
The casting announcement was made a day after CBS confirmed series regular Melina Kanakaredes is leaving "CSI: NY" after six seasons.