Looks like he's about 45, which is extremely young to be a professor, but still leaves a 10 year gap between phd and tenure. I think he just looks very young.
45 is definitely not extremely young to be a professor. Not in the US, where you start as assistant professor. I know plenty of PhD's who graduate and start in a university as assistant professors, age range starting at around 26. My advisor started at 28.
In the US tenure track university faculty typically have three ranks: Assistant Professor (upon hire and prior to tenure) Associate Professor (typically awarded at tenure) and Full Professor. All of these ranks are referred to as "professor", in fact, non-tenure track faculty as also frequently referred to as professor.
