This portrait was completed between the years of 1576-1578 using oils on a canvas measuring 94cm in height and 87cm in width. It resides today within a private collection and so is only seen on rare occasions. El Greco received his first commissions from Philip II at around this time and so would have been familiar with his court, and some of the painters and sculptors within it. As was typical of the time, the sculptor is shown going about his occupation. In other examples, El Greco would include books, easels and the like in order to symbolise the different roles played in society by the subjects of his portraits. Pompeo Leoni shown here is dressed in black with a white ruff, typical of the time in Spain. He is poised besides the sculpture with his easel, as if in mid-thought about how best to continue this piece. Perhaps he is being depicted as if looking at Philip II for the sculpture, whilst in fact El Greco is staring directly at him.

Some experts in Spanish art have drawn a connection in style to a portrait by Diego Velazquez of another sculptor, Juan Martínez Montañés, and Velazquez himself was also prominent within the King's court. Leoni himself was a Italian late Renaissance sculptor and medalist who possessed a similarly expressive manner which would have appealed to El Greco who would do much the same within his own career, particularly as his style evolved over time. El Greco was not entirely comfortable living in Spain but found many opportunities here and received enough respect from patrons to warrant staying in Toledo for a good number of years. He is remembered most for his sprawling religious scenes, but also completed a good number of portraits such as this. The latter tended to be smaller canvases, with reduced detail and within relatively traditional compositions. In time he would allow his studio to complete elements of these so that he could spread himself across a larger number of projects.

Pompeo Leoni moved to Spain in the 1550s and immediately worked on a number of commissions for the King, who clearly appreciated the work that he was producing. It was therefore no surprise that he would be willing to work alongside other imported artists, such as El Greco, in the decades that followed. El Greco himself was originally from Crete but this Greek region was under the rule of Venice at the time. He therefore became connected to the Venetian school before heading to Rome to continue to learn. This was an artist who became used to moving around in search of the finest commissions and so his relocation to Spain would not be something to fear, but rather embrace. Some today even consider him a Spanish artist, such was his impact in the country.