Staab was born in Hays, Kansas and grew up in Ralston, Nebraska. She graduated in 1979 from Ralston Senior High School. Rebecca won the Miss Nebraska USA 1980 title and competed in the Miss USA 1980 pageant held in Biloxi, Mississippi in May 1980. She placed in the top twelve of the nationally televised event, the first Nebraskan semi-finalist in seven years. As of 2007, no other Miss Nebraska USA has placed in the competition since Staab.
On January 11, 2008, Staab made her debut on The Young and the Restless as April Stevens, Paul Williams's former wife and mother of his daughter, Heather Stevens.
Before becoming an actress, Rebecca worked as a model for the famous Ford Agency. She has appeared as a regular in numerous television shows:
Rebecca had a 12-year relationship with actor/writer/director Shawn Thompson, whom she met while they were working together on Guiding Light (1952) (circa 1986-1998).
Ms. Staab is a certified scuba diver. Her other hobbies include horseback riding, rock climbing, mountain biking, kayaking, running marathons and dancing. She is also fluent in French.