I did a node for e2 about him, since while there were nodes about Retief and the Bolo Combat Units, there was no bio of the man himself.
The late joelrosenberg noted in his foreword to Legions of Space that Laumer tends to get overlooked because he was one of the journeyman writers who helped fill the SF magazines of the 1960s while the stars like Heinlein and Frank Herbert were off winning awards with highfalutin' award-winning novels. Laumer never won any awards, but I think years after most of the New Wave has been forgotten, we're still going to be reading about the adventures of Jame Retief, the Bolos, and all the other "Guys Who Get Things Done" who supply the protagonists for Laumer's stories.
I personally first ran into Laumer in the pages of the December 1965 Worlds of IF, which also happened to have the first part of Heinlein's The Moon Is A Harsh Mistress; the Laumer story was the last part of Retief's War, and it sent me off to the various libraries in pursuit of more Laumer. The task was complicated by the fact that Ace, Dell, and other folks kept reprinting different collections of Laumer stories, and in those days there was no easy way to chase down strays. In fact, it wasn't until yesterday evening that I managed to find and read a copy of his first story, "Greylorn", at the Project Gutenberg website. It was a worthwhile chase, though.