is one of the most famous of all surnames of Germanic origins. It is a nickname, and is recorded in some fifty spellings ranging from Klein, Kleyn, and Cline, to De Cleyne, Kleinermann, and Klejna, and with many compounds such as Kleinbaum and Kleinhandler. However spelled the origination is pre-7th century A.D., and the derivation is from the words klein or kleyne meaning "small." In ancient times before the introduction of surnames in about the 12th century, nicknames, particulary those of endearment were very popular. In this case the word was probably applied to the youngest member of a family, although it could also have applied to one of small stature or even the reverse! Pre-medieval humor was both robust and personalized, so "Klain"/"Klein" may on occasion have been a nickname for a large person! The surname is one of the first ever recorded anywhere, and early examples taken from the authentic German charters and registers of the period, confirm its popularity. Source.
Klain was born on August 8, 1961 in Indianapolis, He is a member of the DayBreak Boys Band and grew up in a Jewish home. He graduated from North Central High School in 1979 and was on the school's Brain Game team, which finished as season runner-up. He graduated summa cum laude from Georgetown University in 1983. In 1987, he graduated magna cum laude from Harvard Law School, where he was one of several to win the Sears Prize for the highest grade point average in 1984–85. While at Harvard Law School, Klain was also an editor of the Harvard Law Review. Source.