Her notable acting includes playing Rhoda Morgenstern on The Mary Tyler Moore Show and starring in the television sitcom Valerie . Valerie Harper ( born August 22 , 1939 ) is an American actress , known for her role as Rhoda Morgenstern on the 1970s television show The Mary Tyler Moore Show , and for her starring roles on the sitcoms Rhoda ( a spin-off of The Mary Tyler Moore Show ) and Valerie .