In the article, "Three Paintings by El Greco", Walter Liedtke theorizes that it was the nephew of Cardinal Guevara, Pedro Lasso, who commissioned his portrait.

[1] Conde de Los Arcos (Pedro Lasso), was an established patron of El Greco at the time when this portrait was commissioned.

[1] At the time of Lasso's death, he is said to have owned seven or eight El Greco paintings, although it is unclear whether the portrait of Cardinal Fernando Nino de Guevara was among this group.

[1] Although Guevara had siblings who could have commissioned his portrait, during this time, his sisters were dedicated to various convents and his brother, Rodrigo, lived primarily in the Spanish Netherlands and was likely not in Spain often enough to know the prominence and popularity of the work of El Greco.

In the 1947 film Lady in Ermine, the inquisitor (Rafael Calvo)[dubious – discuss] sits for his portrait and judges a trial involving a Jewish silversmith in love with El Greco's (fictional) daughter.