It is thought that Martini was a pupil of Duccio di Buoninsegna, the leading Sienese painter of his time.

[1] Lippo Memmi painted a similar Maestà for the Palazzo Comunale in San Gimignano shortly afterwards, an example of the enduring influence Simone's prototypes would have on other artists throughout the 14th century.

Perpetuating the Sienese tradition, Simone's style contrasted with the sobriety and monumentality of Florentine art, and is noted for its soft, stylized, decorative features, sinuosity of line, and courtly elegance.

Simone's art owes much to French manuscript illumination and ivory carving: examples of such art were brought to Siena in the fourteenth century by means of the Via Francigena, a main pilgrimage and trade route from Northern Europe to Rome.

He was commissioned to paint a series of frescos for the porch of the Avignon Cathedral of which only the faint sinopia outlines remains.