Galba was the son of the consul Gaius Sulpicius Galba and Mummia Achaica, and in addition to great wealth and ancient lineage he enjoyed the favour of the emperors Augustus and Tiberius. He began his senatorial career before the normal age, became consul (AD 33), received command of the Upper German army (39), and served a proconsulship in Africa (45).
Galba was appointed governor of Nearer Spain in 60 and served in that post for eight years. In 68, believing that the emperor Nero was planning his assassination, Galba accepted (and perhaps even prompted) an invitation from Vindex, the governor of Lugdunensis in Gaul, to head a rebellion against Nero. He then recruited troops in Spain and built up a large following in many other regions of the empire, though Vindex himself was defeated in a battle with the Rhine armies. Nero, deserted by his imperial troops (Praetorian Guard), killed himself on June 9, 68, and Galba was formally accepted as emperor by the Senate. Upon his arrival in Rome as emperor, Galba executed many highly placed Romans, including the praetorian prefect Nymphidius Sabinus, who had been responsible for his accession. His rewards to the Gallic states that had supported Vindex alienated the Lower Rhine army, which on Jan. 2, 69, proclaimed its commander, Vitellius, emperor. Galba had also refused to pay the Praetorians the reward that they claimed for having deserted Nero; and, when he adopted Lucius Piso Licinianus as his successor instead of the former governor of Lusitania, Otho, the latter won the support of the Praetorians, who then killed both Galba and Piso in the Forum.
(Encyclopedia Britannica)
Roman emperor for seven months (AD 68-69). His administration was priggishly upright, though his advisers were allegedly corrupt.