Maximilian peaked in 2016 and holds at current rank #587, with 18,440 total SSA bearers. It's the long, formal version of a name family that has Max and Maximus and Maximo all competing in the same space. Maximilian is the most European, the most historically laden, and the most certain to be shortened — but the shortening is the whole point.
The Humanist Emperor Name
Maximilian is a humanist coinage from the 15th century, created by Holy Roman Emperor Frederick III who combined Maximus (the Latin superlative, "greatest") and Aemilianus (a Roman family name) to create something new. Frederick intended the name for his son as an aspirational blend of two great Roman names. That son became Holy Roman Emperor Maximilian I, and the name spread through European royalty — Habsburg emperors, Bavarian kings, the ill-fated Emperor of Mexico. The Latin roots are impeccable; the history is spectacular.
Max Is Always There
The reason to choose Maximilian over Maxwell or Maximus is that it gives you the grandest possible formal name while landing at the same daily nickname: Max. Max is currently top 200 in the U.S., so a child named Maximilian will share their nickname with many Maxwells and Maxes. But on formal occasions — graduation ceremonies, legal documents, introductions — Maximilian carries a weight that Max alone cannot. This strategy of grand formal name plus casual nickname is well-established in European naming and increasingly popular in American naming.
The Length Question
Maximilian is eleven letters : one of the longer names in the SSA top 1000. Parents sometimes worry this is impractical; in practice, most children with long formal names use their short form by age 2 and the full name primarily for official contexts. The length isn't a problem if Max is where you're landing. Compare Maximilian vs Maximus for the same Max with different historical flavors.