Manhattan was born on January 7, 1956 in Forest Hills, New York. He moved from Queens to Manhattan after he graduated from Archbishop Molloy High School. Manhattan was first seen on a national basis in a coffee commercial of the mid 1970s, in which he played a stock boy in Margaret Hamilton's general store. He worked for the 112th Precinct, standing in police line-ups for $25 a shot. In 1978 he moved to LA. In 1980 he got his first acting job in Without Warning. David was seen first on TV in 1981. He acted in a TV movie called "Crazy times". Also in 1981 he started his guest role in Hill Street Blues. His first real big role he got was in a TV series called "For Love and Honour" on NBC. The series didn't have a long life. David played Rusty Berger. In 1987 he made his first movie called "China Girl". After that another movie followed called "The king of New York. After the 2 movies he played a guest role on "H.E.L.P.". He played in 2 episodes. After that he made another movie called "Mad dog and Glory". Then his big break came in 1993 when he played John Kelly in NYPD Blue. He left the show because of salary dispute with the producer. After that he played in movies like "Jade" and "Gold coast". He got his own TV series called "Michael Hayes. Michael Hayes is a tough but sensitive ex-cop who goes to work in the U.S. Attorney's office in New York City. When his boss is seriously injured in a bombing, Hayes becomes Acting U.S. Attorney, and butts heads with a number of enemies, both inside and outside the law. He also cares for his nephew Daniel and his brother's wife Caitlin, while waiting for his brother Danny to settle into society following a jail stint. The show only lasted one season. From 1998 till 2000 he didn't make one movie or TV series. In 2000 he starred in 2 movies and one TV movie. In 2002 he moved from LA to Miami, Florida. In the same year he opened his own store in Miami. He was also cast as Horatio Caine in the spin-off of CSI, CSI Miami.