Proper Name: 森田まさのり (Morita Masanori)
Masanori Morita started out his professional career in manga as an assistant of Tetsuo Hara (at the time working on Hokuto no Ken). Apart from a few early one-shots (beginning when he was still a teenager in high school), Morita's first published work was his serial Rokudenashi Blues which launched in 1988 during what is now known as the Golden Age of Jump (referring to Weekly Shonen Jump, where it was serialized).
Though it hasn't had the same crossover international success of many other manga from that period of Jump, it has the distinction of matching Dragon Ball (at 42 volumes) as being the third longest-running manga in the magazine's history at the time of its end (beaten by Kochikame and JoJo which later became two of the rare manga to have published over 100 volumes).
Lasting over four-hundred chapters in a weekly magazine with almost no issues missed, this was the only one of his long-running works to never go on hiatus. A year after it ended, he returned to Weekly Shonen Jump with Rookies, his second major work.
It wasn't published as regularly as its predecessor and perhaps as a consequence, didn't fare as well in the weekly ratings or become as much of a staple of the magazine (occasionally going on hiatus). Despite this, by its end it had averaged sales of over two million copies per volume and has become one of the best-selling manga of that period.
Once again, after taking two years off, Morita returned to Weekly Shonen Jump with another series, Beshari Gurashi (expanding on the concept of some one-shots he had published in Weekly Young Jump). Whereas his first two works had been sports-themed manga about high school delinquents (boxing and baseball respectively), his third was the story of a pair of young stand-up comedians.
The series proved unsuccessful in the magazine and ended prematurely after less than a year, though it wasn't officially cancelled, it didn't come back for another year when it was resurrected in Weekly Young Jump (Shonen Jump's sister magazine aimed at an older male demographic who would've likely grown up with Morita's earlier works).
Though it had a number of hiatuses (ultimately, running for more years than Rokudenashi Blues, with less than half the chapters/volumes), it continued until 2015 and was published in nineteen volumes.