She starred in the 1960 musical comedy The Unsinkable Molly Brown for which she won a Tony Award (Best Featured Actress in a Musical) for what The New York Times called her "buoyant" performance as a rough-hewn Colorado social climber.
Returning to the Broadway stage in 1969 after almost a decade of performing in what The New York Times called "dubious delights", Grimes appeared in a revival of Noël Coward's Private Lives as Amanda, winning the Tony Award for Best Actress.