David Letterman has two siblings. They are Gretchen Letterman and Janice Letterman.
Born in 1947 in Indianapolis, Letterman grew up in the Broad Ripple area, about 12 miles from the famed Indianapolis Motor Speedway. He was the middle child, with one older and one younger sister, creating a dynamic that surely contributed to the development of his quick humor and witty comebacks.
In 2000, he told an interviewer for Esquire that, while growing up, he admired his father’s ability to tell jokes and be the life of the party. Harry Joseph Letterman survived a heart attack at the age of 36 when David was a young boy. The fear of losing his father was constantly with Letterman as he grew up.
The elder Letterman died of a second heart attack in 1973 at the age of 57.