The Semovente da 75/34 represented a significant evolutionary step in Italian self-propelled artillery, specifically engineered as an anti-tank platform to surpass the capabilities of the earlier 75/18 model. Developed by Ansaldo, the vehicle was initially intended to utilize the chassis of the P 40 heavy tank, but persistent delays in that program necessitated the use of a modified M 15/42 medium tank chassis instead. This version was designated as the M 42M, with the "M" signifying modificato (modified). The prototype for the 75/34 was officially approved on March 15, 1943.

Technical modifications to the standard medium tank chassis were extensive, most notably involving the relocation of the armored casemate forward by 11 centimeters. The primary armament was the Ansaldo 75/34 gun, characterized by its 34-caliber barrel measuring 2550mm in length. This weapon offered a quantum improvement over the 75/18 gun/howitzer, providing a muzzle velocity of 525 meters per second and a maximum effective range of approximately 8,700 to 9,514 yards. The vehicle's effectiveness against enemy armor was further bolstered by the use of effetto pronto (hollow charge) ammunition. Internal storage typically accommodated 42 to 46 rounds for the main gun.

The Semovente da 75/34 possessed the following technical specifications:

• Weight and Dimensions: The vehicle had a combat weight of approximately 15 to 15.5 tons, standing 1.8 to 1.85 meters tall, making it a low-profile target on the battlefield.
• Propulsion: It was powered by a petrol-fuelled, eight-cylinder SPA 15 TB engine producing between 190 and 192 horsepower.
• Performance: This powerplant enabled a maximum road speed of 38.4 to 40 kilometers per hour and an operational road range of roughly 200 to 220 kilometers.
• Protection: Armor thickness consisted of 30mm for the frontal plates and 25mm for the sides. Later production units, particularly those utilizing the widened M 43 chassis, were sometimes fitted with German-style spaced armor side skirts.
• Secondary Armament: A single 8mm Breda Model 38 machine gun was provided for anti-aircraft and close-in defense, usually supplied with 888 to 1,104 rounds.

Operational records indicate that total production reached approximately 141 units, though the majority were completed under German control following the September 1943 armistice. At least 78 vehicles were manufactured specifically to meet German requirements. In German service, the vehicle was designated as the Sturmgeschütz M 42 mit 75/34 851 (i) and was primarily used to equip anti-tank companies within infantry divisions fighting in Italy. Prior to the Italian surrender, a limited number of units saw combat with the Ariete II Armored Cavalry Division during the defense of Rome. Historians and contemporary reports often categorized the 75/34 as one of the best armored fighting vehicles produced by Italy during the conflict, though its impact was limited by the late date of its introduction.