Presumably first erected in Roman times, it was originally made of wood. After being destroyed by a flood in 1333 it was rebuilt in 1345, this time in stone.
It has always hosted shops and merchants (legend says this was originally due to a tax exemption), which displayed their goods on a table after authorisation of the Bargello (a sort of a lord mayor, a magistrate and a police authority).
It is said that the economic concept of bankruptcy originated here: when a merchant could not pay his debts, the table on which he exposed (the "banca") was physically broken ("rotta") by soldiers, and this practice was called "bancarotta" (broken table). Not having a table anymore, the merchant was not able to sell anything more to anyone.
In order to connect Palazzo Vecchio with the Palazzo Pitti, in 1565 Cosimo I de Medici required Giorgio Vasari to build the famous "corridor", and to enforce the prestige of the place, in 1593 he prohibited butchers to have their banche on the bridge, which were then immediately replaced by gold merchants' ones. The corporative association of butchers had occupied alone the bridge since 1442.
During World War II, the Ponte Vecchio was not destroyed by Germans during their retreat of August 4, 1944, while all the other bridges were (the access to Ponte Vecchio was however closed by destroying the buildings on the two ends). This was allegedly because of an express order by Hitler.