The lead ship of the class was named for August von Mackensen, a prominent military commander during the war.

In response to the Mackensen-class ships, the British Royal Navy laid down the Admiral-class battlecruisers, all but one of which would eventually be cancelled; the sole survivor, HMS Hood, was completed after the end of the war.

The fourth and final Naval Law, passed in 1912, governed the building program of the German navy during World War I.

The Imperial Naval Office (Reichsmarineamt) decided the Navy should construct one battleship and one battlecruiser every year between 1913 and 1917, with an additional unit of both types in 1913 and 1916.

The Imperial dry docks were deep enough only for ships with a draft of 9 m (30 ft), and simply accepting an increased displacement on the same hull as the Derfflinger class would entail a reduction in speed.

[5] The initial design was approved on 30 September 1912, though the heads of the General Navy Department—Vizeadmiral (Vice Admiral) Günther von Krosigk and Konteradmiral (Rear Admiral) Reinhard Scheer—and the Weapons Department head, Vizeadmiral Gerhard Gerdes, had to submit any revisions they deemed were necessary.

Another suggested alternative was to use six 38 cm (15 in) guns in twin turrets, one forward and two aft; Wilhelm II accepted that design on 2 May 1913, though Admiral Friedrich von Ingenohl, the commander in chief of the High Seas Fleet, preferred the 30.5 cm gun of the Derfflinger-class ships.

Coal-fired boilers were preferred because the coal, stored in the sides of the ship, provided additional protection, particularly for the battlecruisers, which carried less armor than their battleship counterparts.

This was necessary because the aft decks of earlier designs were usually awash when steaming at high speed, even in calm seas.

The ships were also equipped with a bulbous bow to reduce drag on the hull, the first time the feature was used in the German Navy.

[9] The ships of the Mackensen class were equipped with four sets of marine-type turbine engines, each of which drove a three-bladed screw propeller that was 4.2 m (13 ft 9 in) in diameter.

[12] The ships' turbines were equipped with Föttinger gears, which significantly improved performance at cruising speeds and provided a corresponding increase in range of about 20 percent.

This was estimated to give a range of up to about 8,000 nautical miles (15,000 km; 9,200 mi) at a cruising speed of 14 kn (26 km/h; 16 mph).

[14][15] The ships' secondary battery consisted of fourteen 15 cm (5.9 in) SK L/45 quick-firing guns mounted in armored casemates along the central superstructure.

[19][12] The Mackensen-class ships were protected with Krupp cemented steel armor, as was the standard for German warships of the period.

Specific figures for the arrangement of the armor layout have not survived, but according to naval historian Erich Gröner "The outfit of Krupp armour was similar to that of the [preceding] Derfflinger class".

They had an armor belt of 300 mm (11.8 in) thickness in the central citadel of the ship, where the most important parts of the vessel were located.

At the launching ceremony, Großadmiral Prince Heinrich gave the speech and Spee's widow Margarete christened the ship.

[24] Construction stopped about 12 months away from completion; Graf Spee was the furthest along of all four ships when work was halted.

[9] Experience at the Battle of Jutland led the RMA to conclude that ships with 38 cm guns, heavier armor, and a higher top speed were necessary.

The Mackensen design was used as the basis for the Ersatz-Yorck class, which incorporated the larger guns and more armor for the main battery turrets and barbettes.

More powerful engines were unavailable to compensate for the extra weight, so the designers were forced to accept a reduced speed.

[28] The RMA filed a report dated 1 February 1918 stating that capital ship construction had ground to a halt primarily for this reason.