The son of Augustus of Saxe-Coburg-Gotha (1818-81) and his wife Clémentine of Orléans (1817-1907), he was born in Vienna as Ferdinand Maximilan Charles Leopold Marie, Duke of Saxony, later suceeding his father as prince of Saxe-Coburg-Gotha.
He was proclaimed prince regnant of autonomous Bulgaria on July 7, 1887 in the Gregorian calendar (the "New Style" used hereinafter), ten months after the abdication of his predecessor Prince Alexander.
Bulgaria's domestic political life was dominated during the early years of his reign by liberal party leader Stefan Stambolov, whose foreign policy saw a marked cooling in relations with Russia, formerly seen as Bulgaria's protector.
On April 20, 1893 at the Villa Pianore in Luccia in Italy, Ferdinand married Maria Luisa Pia Teresa Anna Ferdinanda Francesca Antonietta Margherita Giuseppina Carolina Bianca Lucia Appollonia, Princess of Bourbon-Parma, daughter of Roberto I of Parma.
They had four children:
Following Maria Luisa's death (January 31, 1899), Ferdinand married (February 28, 1908) as his second wife Eleonore Caroline Gasparine Louise, Princess Reuss-Köstritz (1860-1917).
Ferdinand became king of Bulgaria upon the country's declaration of independence from the Ottoman Empire on October 5, 1908. The two Balkan Wars of October 1912-July 1913 saw the partial reversal of initial Bulgarian territorial gains.
Ferdinand abdicated on October 3, 1918 after Bulgaria's defeat in World War I, which she had entered (October 1915) on the side of Germany, Austria-Hungary and the Ottoman Empire in an attempt to reverse the losses of 1913.
He died in Burglassschloßen in Coburg, and is buried in St. Augustin’s Catholic Church.
See also: List of Bulgarian monarchs