He was suffect consul for the nundinium of June to July AD 99 as the colleague of Publius Sulpicius Lucretius Barba.
Ronald Syme, noting Afer's tribe was "Galeria", states that it is attested for only one city in North Africa, Hadrumetum, while later members of the gentilicium Memmius "tend to come from Bulla Regia or Gigthis"; on the other hand, Syme states the cognomen Afer is well-attested in Spain, while he counted eighteen instances of the gentilicium Memmius in the Spanish provinces.
[3] Afer was the father-in-law of Tiberius Catius Caesius Fronto, the son of the poet Silius Italicus.
[9] The men selected to be consuls in the year 99 numbered more than usual, and can be considered to reflect the emperor Trajan's choices, and the factions in the Senate he looked to for support.
Of the possibly as many as ten suffect consuls for that year, five are known; of these, two are provincials, two Italians, all of them active in government; the fifth, Afer's colleague Lucretius Barba, is only a name.