The actress with the longest-running TV career is Betty White, who has been acting since 1939.
Betty White is an American actress, comedian, and author who has been acting since 1939. She is best known for her roles on sitcoms such as The Mary Tyler Moore Show, The Golden Girls, and Hot in Cleveland. Her career has spanned eight decades, and she is the only actress to have won an Emmy Award in every decade since the 1950s. She is also the oldest person to ever host Saturday Night Live.