Zelda was the co-founder and producing director of Arena Stage, Washington, DC 1950-1990 and is considered a parent of the regional theatre in America. In December 1997, President Clinton awarded her a National Medal of the Arts, the country's highest award for work in the Arts, and in 1998 she was inducted into the Theatre Hall of Fame, the first person outside of New York to be elected. She directed many of Arena's plays including Inherit the Wind which toured to Moscow and Leningrad in 1973, After the Fall which her company performed in Hong Kong in 1980 and The Crucible, which was part of the Israel Festival in Jerusalem in 1987. In 1985, she was awarded The Acting Company's John Houseman Award for commitment and dedication to the development of young American actors and the Commonwealth Award for Distinguished Service in Dramatic Arts. In 1976, the New York commercial theatre world awarded her and Arena Stage its highest honor, the Antoinette Perry (TONY) Award, the first to be given to a company outside of New York. She was for three years artistic director of The Acting Company, the classical company that tours America, and is past President of the Theatre Communications Group.