His father , Harry Joseph Letterman ( April 15 , 1915 -- February 13 , 1973 ) , was a florist . His mother , Dorothy Marie ( Hofert ) , a church secretary , has been an occasional figure on the show , usually at holidays and birthdays .
His father , Harry Joseph Letterman ( April 15 , 1915 -- February 13 , 1973 ) , was a florist of English ancestry ; his mother Dorothy Letterman ( nee Hofert , now Dorothy Mengering ) , a church secretary of German ancestry , has been an occasional figure on the show , usually at holidays and birthdays .