Born in Vienna on 13 May 1717, Maria Theresa was the eldest daughter of Elisabeth Christine of Brunswick-Wolfenbüttel and Emperor Charles VI, the last Habsburg Emperor of the Holy Roman Empire. As his son Leopold Johann died as an infant in 1716, Charles VI promulgated the Pragmatic Sanction, so that Maria could succeed the Habsburg monarchy after his death. Maria Theresa was the last of the House of Habsburg and the only female ruler of the Habsburg dominions.

Maria had large blue eyes, fair hair with a slight tinge of red, a wide mouth and a notably strong body. During her early years she was a serious and reserved child, enjoyed singing and archery. She also enjoyed her participation in the opera productions staged by the imperial family, often conducted by Charles VI. She received the upbringing and education typical of a daughter of dynastic lineage, focusing on courtly deportment, music, dancing, painting and languages. However, though she was to inherit the Habsburg throne, she was not well acquainted with the affairs of state. Since she was 14, she was allowed by her father to attend the meetings of the council, but never bothered to discuss the affairs of state with her. In reality, Charles never prepared his daughter for her future role as sovereign.

Prince Eugene of Savoy, the trusted adviser of Charles VI, wanted Maria Theresa to marry a powerful prince. But, the emperor allowed his daughter to marry for love and in 1736 Maria Theresa and her beloved Duke Francis Stephen of Lorraine, France, were wed. During those days, Maria Theresa was one of the few people in her age who married for love. She loved her husband dearly and passionately and had 16 children by him.

When Emperor Charles VI died in October of 1740, he left Austria in a precarious condition, bankrupted by the Turkish war and the War of the Polish Succession. In fact, the state was in a severe fiscal crisis, total debt amounting to 103 million florins, with only 87,000 florins available on hand. Lastly, the realm was virtually defenseless, as the army had been reduced, soldiers were poorly trained and were scattered in small areas, from the Austrian Netherlands to Transylvania and from Silesia to Tuscany. In that critical situation, Maria Theresa had the supreme responsibility thrust upon her at the age of 23, without anything in the way of formal preparation, without the least acquaintance with affairs of state. Though the Duchy of Austria and the Netherlands, Bohemia and Hungary were quick to accept Maria Theresa as their Empress, Saxony, Prussia, Bavaria and France repudiated the sanction they had recognised during the lifetime of the deceased Emperor and under the leadership of Frederick II, King of Prussia, those powers formed a coalition against Maria Theresa.

On 16 December 1740, Frederick II invaded Silesia, an Austrian province, and claimed it for his kingdom. On the other hand, Bavaria and France also started invasion of Habsburg territories. This led to the War of the Austrian Succession in 1740. Unfortunately, with the exception of a few administrators she had managed to appoint, Maria Theresa had never found an efficient general during the war. In that grave situation, she tactfully managed to secure the vital support of the Hungarians for the war effort. The war continued for eight years and ultimately ended in 1748, when Austria was forced to let Prussia keep Silesia and to accept the loss of three of its Italian territories to France. However, despite the loss, Maria Theresa successfully defended her rule over most of the Habsburg Empire.

Unfortunately, the war did not end there. In 1756 Fredrick II once again waged war against Maria Theresa’s empire, which led to the Seven Years War. During that time, Maria tried in vain to reclaim Silesia. But, the war ended with the Treaty of Hubertusberg on 15 February 1763, which left Silesia, one of the richest Habsburg provinces, in Fredrick’s hand.

During her reign, Maria Theresa promulgated institutional, financial and educational reforms. Apart from promoting commerce and taking steps for agricultural development, she also reorganised Austria's crumbling army. She increased the size of the army, reformed the military and the judiciary, and established a high court. She established new structures in the educational system with the objective of introducing compulsory schooling and standardized measurements and weights. At her instance, the capital city Vienna was beautified, streets were paved and the stock exchange (Boerse) and Burgtheater were constructed. The Schönbrunn Palace, originally a hunting lodge, was enlarged and transformed into a prestigious landmark, which became Maria Theresa's favourite palace.

Maria Theresa was a devoted Roman Catholic and strongly believed that religious unity was necessary for a peaceful public life. She explicitly rejected the idea of religious tolerance, regarded both the Jews and Protestants as dangerous to the state and actively tried to suppress them. Protestants were persecuted and expelled to be resettled in thinly populated regions of what is now Romania. Possibly, she was the most anti-Jewish monarch of her time. She had the intention to deport all the Jews by 1 January 1745, but having accepted the advice of her ministers, who apprehended that the number of the deportees could reach around 50,000, she deferred the deadline till June. Later, the expulsion orders were retracted in 1748, due to pressures from other countries, including Great Britain. Though she even advocated for a state church, she never allowed the Church to interfere with the prerogatives of a monarch and controlled the selection of archbishops, bishops and abbots.

During her entire life, Maria Theresa showed no tolerance towards immorality. A chastity court was initiated at her instance, for the prosecution of the prostitutes, adulterers, homosexuals, sodomites and even sexual intercourse between members of different religions. Depending on the degree of crime, the offenders had to face whipping, deportation or even the death penalty. But, someone who was never charged by the chastity court was her own adulterous husband.

In the later part of her reign, she focused on reforming laws as an enlightened monarch. However, it is considered by many that she did not act solely out of care for her population, but rather to strengthen the economy of the Habsburg territories, especially after the loss of Silesia.

Maria Theresa was described by her contemporaries as a very beautiful woman, especially when she was young. Probably she was painted many times more than any other woman of her time and her position of power was not the only reason behind it. It is said that he had a round face with slightly reddish blonde hair and large, expressive, light blue eyes, and an upbeat expression. However, she became somewhat sluggish and languid after going through childbirth numerous times. Despite her immense responsibility and commitment, she took proper care of her 11 daughters and five sons, and arranged to impart them comprehensive education. Among her 16 children only 10 reached adulthood and among them two were future emperors and one was an elector of Cologne. Apart from that, Marie Antoinette, the future wife of King Louis XVI of France was one of her daughters.

By asserting her power in trying times, Maria Theresa gained a great deal of respect. In 1745, when her husband became the Emperor of the Holy Roman Empire, Maria Theresa acquired the title of Empress. She was the only female sovereign in the history of the House of Habsburg, who became pivotal during the era of enlightened absolutism, which saw rulers in Europe increasingly valuing rationalism and supporting human rights.

After reigning 40 years, Maria Theresa died of pneumonia on November 29, 1780, at the age of 63 in her hometown, Vienna.