She stayed for 69 episodes
Donna Reed and Ann McCrea (Midge)
Ann McCrea (born February 25, 1931).
Ann McCrea, also known as Ann McCrea Borden, is an American former actress best known for her role as Midge Kelsey in sixty-nine episodes (1963 to 1966) of the ABC situation comedy series, The Donna Reed Show.
McCrea was an original member of the board of directors of the Donna Reed Foundation when it was established in 1986 and was involved in the early years of the Donna Reed Festival held in Denison, Iowa.