Maximiliano is the Spanish and Portuguese form of Maximilian, a name the Emperor Frederick III is said to have coined in 1459 for his son by joining the Roman names Maximus, "greatest", and Aemilianus; it is also explained as a derivative of Maximilianus, "the greatest". Maximilian I of Mexico, the Habsburg emperor executed in 1867, gave the name a dramatic place in Mexican history. Maximiliano has been in the US top 1000 all century, moving from number 946 in 2000 to a peak of number 251 in 2019 and number 280 among boys' names in 2025.