Alt was born at Frankfurt am Main in 1789, where he received his early artistic education. Later he moved to Vienna and entered the Academy. He soon became noted as a landscape painter and made various journeys throughout Austria and Italy, painting, as he went along, views in the neighborhood of the Danube and in the city of Vienna.
In later life Alt painted a lot in watercolor; he was also a lithographer. In 1830 the future Emperor Ferdinand I of Austria began a project to commission paintings of the most beautiful views in the Empire. Alt, and his eldest son, Rudolf von Alt painted about 170 of the 300 works executed before the scheme came to an end in 1849.