Prior to the August 2012 debut of the compact Cadillac ATS, the first vehicle produced on the GM Alpha platform, Cadillac's smallest vehicle was the mid-size CTS. The CTS was as expensive as compact competitors like the Audi A4, the BMW 3-Series and the Mercedes-Benz C-Class but was noticeably larger and heavier, comparable in size and weight to the mid-size BMW 5-Series. Although Cadillac believed that customers would favor a 5-series sized car at a 3-series price, that assumption proved to be incorrect. Cadillac's research found that target customers who already owned vehicles like the 3-series or A4 didn't want a larger vehicle. General Motors began development of a platform to underpin a smaller car that would satisfy these target customers; that car would eventually become the ATS.
During the early development of the Cadillac ATS, General Motors engineers determined that downsizing the GM Sigma II platform that underpinned the second-generation CTS would result in a vehicle that was too heavy and that using an economical, front-wheel drive platform would sacrifice performance. Under the leadership of Dave Leone, General Motors engineers created a brand-new platform which was designed to be light and compact, capable of handling both rear- and all-wheel drive configurations and having a near 50/50 weight distribution. The new platform developed by the General Motors engineers for the ATS is now called the GM Alpha platform.
General Motors began assembling Cadillac ATS sedans intended for sale to customers on 26 July 2012.
General Motors began assembling third generation Cadillac CTS sedans intended for sale to customers on 16 September 2013.
^"GM Poised to Thrive with New Cars, Tech, Reuss Says" (Press release). Traverse City, Michigan: General Motors. 2011-08-04. Archived from the original on 2012-11-21. Retrieved 2012-11-21. "Cadillac next year will launch the XTS large luxury sedan and a compact luxury sports sedan codenamed ATS, models that will bracket the CTS Sedan, Coupe and Wagon family, Reuss said at the Center for Automotive Research’s Management Briefing Seminars."
^"Production Begins for 2013 Cadillac ATS" (Press release). Detroit, Michigan: General Motors. 2012-07-26. Archived from the original on 2012-11-22. Retrieved 2012-11-22. "The first 2013 Cadillac ATS compact luxury sport sedan intended for public sale was built today at the Lansing Grand River assembly plant in Michigan, culminating a massive design and development project."
^VanHulle, Lindsay (2013-09-16). "New Cadillac CTS Millionth Car Off Line at GM's Lansing Grand River Plant". lsj.com (www.lansingstatejournal.com). Business. "General Motors Co.'s newest Cadillac rolls onto dealer lots starting next month — and the Detroit automaker believes it will have another Lansing-made hit on its hands. The first upgraded 2014 Cadillac CTS sedan that will be sold through a dealership came off the line Monday at GM’s Lansing Grand River assembly plant..."
^"Lansing Grand River Builds Millionth Cadillac" (Press release). Lansing, Michigan: General Motors. 2013-09-16. Archived from the original on 2013-11-08. Retrieved 2013-11-08. "The millionth Cadillac built at the Lansing Grand River Assembly Plant rolled off the line today. Fittingly, the milestone vehicle is an early model of the redesigned 2014 CTS sedan, which goes on sale in October."
^Zenlea, David (2013-03-26). "2014 Cadillac CTS First Look". Automobile. Source Interlink Media. OCLC44212172. Archived from the original on 2013-08-03. Retrieved 2013-08-02. "The 2014 CTS rides on a stretched version of the Alpha platform that underpins the ATS."