The sedan was unveiled during Moscow International Automobile Salon on 29 August 2012, and the station wagon version followed during the 2012 Paris Motor Show in the following month.

[9] In July 2019, the "Atenza" nameplate was renamed into Mazda6 moniker in the Japanese domestic market as part of Mazda's new global naming structure.

[13] For 2014, new features included SCBS (smart city brake support) as standard equipment in the Atenza 20S and XD, increased efficiency for Skyactiv-G 2.5 engine models to 16.0 km/L (6.3 L/100 km; 45 mpg‑imp; 38 mpg‑US) (JC08 mode), new slide glass sunroof option for Skyactiv-D 2.2 engine models, addition of XD L-package (6-speed manual transmission, leather seats), Bose 11-speaker sound system with Centerpoint 2 surround sound become standard in XD L-package models, and addition of deep crystal blue mica body color to total of seven body color options.

The 2014 Atenza Sedan design concept was a Mazda Atenza Sedan with Skyactiv-D engine, Skyactiv-MT 6-speed transmission, original aero parts, Brembo brake calipers, Soul red body color, aluminum wheels, semi-bucket seats, and Alcantara interior upholstery.

[citation needed] The 2014 Atenza Wagon design concept was a Mazda Atenza Wagon with Skyactiv-D engine, Skyactiv-MT 6-speed transmission, metal-decorated instrument panel, dashboard with leather upholstery and stitching, and metal decoration at trunk board.

US and Canadian models with the Skyactiv-D diesel engine available in Europe and Asia were originally planned for the second half of 2013, but that was delayed due to emissions issues.

In Canada, GX, GS and GT trim levels were offered; all had the manual transmission as standard equipment.

[citation needed] The 2015 Mazda6 was named a Top Safety Pick Plus by the IIHS[25] when equipped with available Smart City Brake Support.

They cited shifting consumer preferences to larger crossover SUVs, adding that the similarly priced CX-5 outsells the Mazda6 by a margin of 9-to-1.

i-ELOOP is a regenerative engine braking system that uses the free wheeling alternator to capture energy when coasting.

While the base Sport and Touring trims receive the previously-available 187 hp (190 PS; 139 kW), 2.5L Skyactiv I4 gasoline engine, the Grand Touring, Grand Touring Reserve, and Signature trims receive a 2.5-liter Skyactiv turbocharged gasoline inline-four engine that produces 227 hp (230 PS; 169 kW); 250 hp (253 PS; 186 kW) on high octane fuel.

[33] A software update was available for 2018 Mazda6 owners that added these capabilities, and newer Mazda6 models are equipped with these features from the factory.

[40][41] During the first race at Rolex 24 At Daytona in January 2013, all three cars had to retire in the first few hours due to engine failure.

[42][43] Mazda ultimately won the 2013 GX class championship, beating rivals Porsche and Lotus.