He gained renown as an accommodating, versatile, parsimonious and methodical lawyer, enabling him to become mayor and then magistrate of Écija, then counsellor of Castile and finally ambassador to England in 1487.
Basing himself in an Augustinian monastery and later near the Strand, de la Puebla was also sent instructions from Ferdinand to negotiate an alliance with James IV of Scotland and arrange for a marriage between that king and Joanna of Aragon (1455–1501), illegitimate daughter of Don Fernando.
Though he proved a successful ambassador to England, he gained a reputation as both greedy and stingy, with accusations that he lived in poor housing and even skimped on paying for food, preferring instead to be invited to dine at the English royal court.
[4] By this time Catharine had been widowed and de Puebla began negotiations for her re-marriage to Arthur's younger brother, the future Henry VIII of England, in an attempt to maintain the Anglo-Spanish alliance and continue their isolation of France.
His second embassy ended on 21 June 1508 on Ferdinand's orders, delivered by Fuensalida, though de Puebla stayed in England until his death in April the following year.