It is considered one of the most personal of Gian's work, and the bust expresses Piccolomini Bonarelli who was the wife of the famous Matteo, one of Bernini's co-workers and students. Bust of Costanza Bonarelli is an exceptional sculpture since it breaks the main tradition of the 17th-century portrait reviews and sculpturing the styles of the next century.

Due to his religious fervour and the fact that the majority of his commission was provided by the religious figures, most of his work was religious by theme and nature. However, due to the influence of several classical collections of the Scipione Borghese, one of his patrons Bernini had an interest in the mythological techniques and figures. Also, due to the patronage which he was driven by, he created a series of portraits that were both in sculpted busts and painted forms.

Drawing from the influences of his master and the Mannerist art, Bernini created dynamic and swirling compositions in many of his sculptures that were to be viewed from all directions. Although most of his figures, including the Bust of Costanza Bonarelli are always idealized like the perfected version of reality, he manages to bestow most of them with unique features and imbue them with the human emotion. In his artistic work, Bernini did not neglect the careful details that play a significant role to bring his figures to life. Through the careful combination of sculpture, painting, and architecture Gian was able to develop what artworks could encompass.

One of the foremost style and workaholics in the art history, Lorenzo toiled uniformly throughout his artistic career, working for seven hours each day without any pose even in the old age period. To achieve the beauty of his sculptures, Bernini used several styles and methods which include the casting technique famously known as the lost wax and the painstaking process. In this technique, the first step is to develop a wax model of the sculpture. Concerning the case of the baldachin, Bernini used real-life objects such as lives to create the natural appearance. He also used molten bronze and wax in the design and execution of the Bust of Costanza Bonarelli.

The sculpture represents Costanza Bonarelli, with whom the Italian artist falls in love with when her husband was Bernini’s assistant in 1636. In this sculpture, Bernini is expressing the most poignant moment and communicating the event in the most dramatic way by the use of exuberant movements, emotive facial expressions and the feasts of technical mastery. From the spiralling columns of the sculpture that draws a viewer's eyes heavenward to the main flutters of fabric in the portrait bust; all of the artistic work provides the scene of being the snapped moment of stillness in a frenzy of motion.