Having filled with success the offices of quaestor and praetor, he was consul in 120. He was appointed by Hadrian as one of the four proconsuls to administer Italia, then Asia. The Emperor Hadrian adopted him as his son and successor on 25 February 138, after the death of his first adopted son Lucius Aelius. The condition was that Antoninus would in turn adopt Marcus Annius Verus, the son of his wife's brother, and Lucius, son of Aelius Verus, who afterwards became the emperors Marcus Aurelius and Lucius Verus