The move has been expected in recent weeks and new Cadillac boss Johan de Nysschen signaled it to Automotive News in a story published Monday.
Cadillac spokesman David Caldwell said the brand expects the office, including display and event space, in the trendy Soho neighborhood of Manhattan to open around the second quarter of 2015.
GM, in today's statement, said the move will establish the brand as a separate business unit.
"With the relentless upward repositioning of successive new-generation Cadillac products, the next logical step is to provide Cadillac more freedom to cultivate the brand in pursuit of further global growth," GM President Dan Ammann said in a statement.
De Nysschen, who took over the brand in August, told Automotive News that the move is important for marketing.
"There are a great number of benefits to putting at least some of our marketing people in a world where they can be in regular contact with not only premium customers, but be more immersed in the lifestyle of people who shop for premium brands," de Nysschen said.
De Nysschen told The Detroit News he expected the New York office to employ about 120 people.
Caldwell said the move would only affect sales and marketing, while product development, design, engineering and research and development staff would remain in place, mostly in the Detroit area.
De Nysschen, in his previous role as head of Nissan Motor Co.'s Infiniti brand, relocated the unit from Yokohama to Hong Kong, in part to give the Infiniti team more autonomy from the Japanese parent and the opportunity to explore new ways to expand in global markets.
GM has been on a similar quest to expand the 112-year-old Cadillac, one of the world's oldest surviving brands, beyond its home base, while resurrecting Cadillac's earlier status as one of the world's top luxury vehicles. De Nysschen is Cadillac's third leader in two years.