He was born as near Terracina, "on the left as you go towards Fundi" in the words of Suetonius. Galba's father attained the consulship, and although he was short, hunchbacked and only an indifferent speaker, was an industrious pleader at the bar. His mother was Mummia Achaica, the granddaughter of Catullus. They only had one other child, an elder son called Gaius who left Rome after squandering the greater part of his estate, and committed suicide because Tiberius would not allow him to take part in the allotment of the provinces in his year.
He came from a noble family and was a man of great wealth, but was unconnected either by birth or by adoption with the first six Caesars. In his early years he was regarded as a youth of remarkable abilities, and it is said that both Augustus and Tiberius prophesied his future eminence.
He became Praetor in 20, and consul in 33; he earned a reputation in the provinces of Gaul, Germania, Africa and Hispania (Iberia, comprising modern Spain and Portugal) for his military capability, strictness and impartiality. On the death of Caligula, he refused the invitation of his friends to make a bid for the empire, and loyally served Claudius. For the first half of Nero's reign he lived in retirement, till, in 61, the emperor bestowed on him the province of Hispania Tarraconensis.
In the spring of 68, Galba was informed of Nero's intention to put him to death, and of the insurrection of Julius Vindex in Gaul. He was at first inclined to follow the example of Vindex, but the defeat and death of the latter renewed his hesitation. The news that Nymphidius Sabinus, the Praetorian Prefect, had given him his favour revived Galba's spirits. Until now, he had only dared to call himself the legate of the senate and Roman people; after Nero's suicide, he assumed the title of Caesar, and marched straight for Rome.
Following Nero's death, Nymphidius Sabinus sought to seize power prior to the arrival of Galba, but he could not win the loyalty of the Praetorian guard and was killed. Upon Galba's approach to the city in October, he was met by soldiers presenting demands; Galba replied by killing many of them.
Galba's primary concern during his brief reign was in restoring state finances, and to this end he undertook a number of unpopular measures, the most dangerous of which was his refusal to pay the praetorians the reward promised in his name. Galba scorned the notion that soldiers should be "bribed" for their loyalty. He further disgusted the mob by his meanness and dislike of pomp and display.
His advanced age had destroyed his energy, and he was entirely in the hands of favourites. Three of these - Titus Vinius, who became Galba's colleague as consul, Cornelius Laco, the commander of the Praetorian Guard and Galba's freedman Icelus Marcianus - were said to virtually control the emperor. The three were called "the three pedagogues" because of their influence on Galba. All this made the new emperor gravely unpopular.
Galba, a man of enormous personal wealth, soon displayed dire meanness. A commission was appointed to recover Nero's gifts to many of the leading figures of Rome. His demands were that of the 2.2 billion sesterces Nero had given away, he wanted at least ninety percent to be returned.
This contrasted wildly with the blatant corruption among the officials Galba himself appointed. Many greedy and corrupt individuals in Galba's new government soon destroyed any goodwill towards Galba which might have existed among the senate and the army.
The worst of these corrupt officials was said to be the freedman Icelus. He was no only rumoured to be Galba's homosexual lover, but rumours told of him having stolen more in his seven months in office than all of Nero's freedmen had embezzled in 13 years.
Galba, Suetonius says (Vita Galbae 22), was "more prone in his passion toward males," whom Galba preferred "hard-bodied" and "past their...pronior (more prone) would indicate that Galba, too, was bisexual.
On January 1, 69, two legions in Germania Superior refused to swear loyalty to Galba and toppled his statues, demanding that a new emperor be chosen; on the next day, the soldiers of Germania Inferior also rebelled and took the decision of who should be the next emperor into their own hands, proclaiming the governor of the province, Vitellius, as emperor.
This outbreak of revolt made Galba aware of his own unpopularity and of the general discontent. In order to check the rising storm, he adopted as his coadjutor and successor L. Calpurnius Piso. The populace regarded the choice of successor as a sign of fear, and the Praetorians were indignant, because the usual donative was not forthcoming.
M. Salvius Otho, formerly governor of Lusitania, and one of Galba's earliest supporters, disappointed at not being chosen instead of Piso, entered into communication with the discontented Praetorians, and was adopted by them as their emperor. Galba, who at once set out to meet the rebels - he was so feeble that he had to be carried in a litter - was met by a troop of cavalry and was butchered near the Lacus Curtius. Piso was killed shortly afterwards. According to Plutarch, during Galba's last moments he offered his neck, and said, "Strike, if it be for the good of the Romans!"
Altogether around 120 people claimed the credit for killing Galba, being anxious to win Otho's favour and hoping to be rewarded. A list of their names was drawn up, which fell into the hands of Vitellius when he succeeded Otho as emperor. Every one of them was executed.