Few YEARS, really. In the novels, he quickly traded command inexperience for some serious daddy issues. Got over them eventually, but following that there wasn't much else to explore with him IMO. However, you could argue that per the novels he was the Captain with the longest unbroken command of any Enterprise CO in history, being in charge of the Enterprise-B from 2293 to 2311 (Kirk had two Enterprises over 28 years, but with various breaks in between). Garrett may be second in line per the novels, if she was indeed the Enterprise-C's only CO between 2332 and 2344.