The new 'CSI: Crime Scene Investigation' spin-off stars Patricia Arquette as Special Agent Avery Ryan, who is in charge of the Cyber Crime Division at Quantico, Virginia, reported Entertainment Weekly.
MacNicol will star as Stravros Sifter, assistant director for the Cyber Crime Division and Ryan's supervisor.
MacNicol's character is described as "a shrewd and savvy networker" and "a charmer with a hint of malice".
The new CBS police procedural show also features Community's Charley Koontz as Agent Daniel Grummitz.
MacNicol is best known for playing lawyer John Cage in 'Ally McBeal'. He has since appeared in '24' and 'NUMB3RS'.