How did J. Edgar Hoover Become Head of FBI at only 29 Years of Age?

by RoryJSK

On r/History there is a trending thread about the Osage people and the book "Killers of the Flower Moon: The Osage Murders and the Birth of the FBI.”

The thread links a PBS article which talks about the events, and in the article it mentions that J. Edgar Hoover was made head of the FBI at 29 years old.

https://www.pbs.org/newshour/amp/arts/the-forgotten-murders-of-the-osage-people-for-the-oil-beneath-their-land

How was it that Hoover became looked at, and ultimately tapped on the shoulder for, this position, at such an early age? I imagine he was a big proponent for a federal bureau, but I would have thought his age would preclude his consideration.

For example 29 would be the equivalent age of a Captain in the U.S. Army today—whereas I would expect someone at least ten years older, a Major or higher rank, to be considered a more appropriate candidate to head an entire federal agency—even an infantile one.

Jetamors