After her stage debut in "As You Like It", Helmond began working in New York City in 1955. She later ran a summer theatre in the Catskills for three seasons and taught acting in university theatre programs. She made her television debut in 1962, but did not achieve a high profile until the 1970s. She also acted on stage, earning a Tony award nomination for her performance on Broadway in Eugene O'Neill's "The Great God Brown" (1973). Her other appearances in Broadway productions included roles in "Private Lives", "Don Juan" and "Mixed Emotions".