She has been instrumental in creating a costuming "look" for a plethora of bands and their music videos, including The Fugees, Bush, Puff Daddy, Luis Migel, Spice Girls and M-People. On the commercial front Mannix' credits range from cutting edge Coca-Cola spots to Pacific Bell. Her additional clients include Cadillac, American Express, Levi 501, Mercedes Benz, Hallmark, Burger King, Pepsi and AT&T.

Mannix served as costume designer for television series and MOW's including: Tomorrow Man for FOX Television; Christmas in Connecticut for TNT; Dirty Dancing for CBS; and The Renegades for Paramount TV.

Mannix feature film credits include: Peter Bogdanovich's At Long Last Love; Joe Hanwright's Uncle Joe Shannon; Walter Hill's The Warriors; Robert Greenwald's Xanadau; and Walter Hill's The Long Riders.

Mannix is currently working with several commercial directors and lives in Los Angeles with her family.