The Przemysl family is (according to legend) descended from a Czech plowman of the same name who was chosen by Libuse, a royal princess, as her husband.

As the head of the Přemyslids who dominate the environs of present-day Prague, Bořivoj had declared himself kníže—in Latin dux, which means sovereign prince—around the year 870.

His title will be later translated by German scholars as "duke" of the Bohemians (Czechs).

Bořivoj had been recognized as such around 872 by his overlord Svatopluk I of Great Moravia, who had dispatched Bishop Methodius to begin the conversion of the Bohemian Slavs to Christianity.

Borivoj and his wife Ludmila had been baptized by Methodius, probably in 883, and the latter had become an enthusiastic evangelist, although the religion fails to take root among Bořivoj's subjects.

Borivoj had been deposed in the years 883/884 by a revolt in support of his kinsman Strojmír.

He was restored in 885 only with the support of his suzerain Svatopluk of Moravia.

When Borivoj dies about four years later, his sons still minors, Svatopluk takes over the rule of Bohemia himself.

As with most of the early Bohemian rulers, Borivoj is a shadowy figure; exact dates for his reign and vital statistics cannot be established.

Nonetheless, several major fortifications and religious foundations are said to have dated from this time.

In old Czech legends he is said to have been son of a Bohemian prince named Hostivít.