Hiroshi "H" Suzuki is an agent with the Japanese CIRO.
That acronym stands for the Cabinet Intelligence and Research Office, also known as the Japanese Secret Service. His direct boss there is Colonel Kimura, the head of the department. It is obvious from the meeting we follow at the beginning of the first adventure that they have known and worked with each other for some time and that Suzuki is a valued and highly experienced operative.
We also learn that Suzuki considers the Colonel to be his "adoptive uncle and mentor". The relationship between Suzuki and Kimura is important. Suzuki's father had never been in the picture and his mother had dies when he was 16. It was the Colonel who took charge of him and from that day on his career path in the CIRO was a sure thing. The fact that Suzuki clearly enjoyed that line of work was just a good coincidence.
The "H" is his nickname and the one used most ofter by his friends.
Suzuki has had a wide education with first his normal schooling in Japan followed by earning a degree at Oxford. "At the same time H continued his training in the arts of weapons, battle, diplomacy, secrecy and subterfuge. Over the years he'd developed into an outstandingly talented operative. He was a natural, who'd excelled at every challenge and he'd never considered any other profession."
Suzuki must have a considerable amount of money because in addition to sporting an expensive Rolex Submariner watch, he drives a luxury car with his dream Bentley W12 engine (apparently that is rather unusual), a vehicle that is also fitted with "serious electronic 'gizmos' and state of the art extra features". Both the watch and the car are but two indications that Suzuki knows how to appreciate the finer things and apparently has the financial means to do so.
When he isn't out stopping would-be world conquerors.