The legacy of Ambrose has emerged mainly from his pastoral work: the preaching of the Word of God combined with the doctrine of the Catholic Church, attention to issues of social justice, the welcome to people from distant areas, the complaint of the errors in the civil and political life.
The work of Ambrogio left a deep impression: he introduced in the Western church many elements from Eastern liturgies, especially songs and hymns. The liturgical reforms were maintained in the diocese of Milan by the successors and formed the nucleus of the Ambrosian Rite, survived to the harmonization of the rites and to the establishment of the one Roman rite. His figure has also inspired the award Golden Ambrogino , which is the unofficial name of the honors conferred by the city of Milan.

The Basilica of St. Ambrogio, the burial place of the saint, is not only a monument from the early Christian and Middle Ages, but also a key point in the history of Milan and the Ambrosian church. Traditionally considered the second most important church in the city, the Basilica of of St. Ambrogio is a model case of the Lombard Romanesque, as other contemporary examples have now been destroyed or radically transformed. It was certainly an example for future developments in the area of influence of the Romanesque Lombard then exceeded regional boundaries today. It is the expression of an intense architectural renovation, especially in the design of lighting and space. On the one hand, the light comes mainly from the windows of the facade (while the women's galleries are blocking the passage side), which determines a longitudinal joining. The resulting effect is the accentuation of the structural masses, especially to the bottom, where the greater the shadow. On the other hand, space is no longer conceived how early Christian, in a unified and mystical, but human and rational way: hence, the division into geometric spaces well defined, and the exaltation of the static elements that differ even so color from non-static, both outside and inside.

In the square in front of the basilica there is "the pillar of the devil." This is a column of Roman period, which has two holes, subject of a legend according to which the column witnessed a fight between St. Ambrogio and the devil. The devil one trying to pierce the saint with horns instead ended up putting them into the column. After trying for a long time to break free, the demon broke free and, terrified, escaped. According to popular tradition the holes smells sulfur and placing ear to the stone you can hear the sounds of hell.

On a granite column (ancient Roman) inside the Basilica, stands the "Serpent of Moses": It is a bronze sculpture which are directed prayers to ward off certain types of illnesses and it is said that the end of the world will be heralded by the descent snake from this column on which is nestled.

In the basilica is set the first act of the opera by Giuseppe Verdi The Lombards in the First Crusade.
The Royce Hall of the UCLA [University of California, Los Angeles (1929)] was inspired by the facade of St. Ambrogio.