He knew many of the writers of science fiction in the first half of the twentieth century. As a literary agent, he represented some 200 writers, and he served as agent of record for many long-lost authors, thereby allowing their work to be reprinted in anthologies. He was Ed Wood's "illiterary" agent. Ackerman was credited with nurturing and even inspiring the careers of several early contemporaries like Ray Bradbury, Ray Harryhausen, Charles Beaumont, Marion Zimmer Bradley, and L. Ron Hubbard. He kept all of the stories submitted to his magazine, even the ones he rejected; Stephen King has stated that Ackerman showed up to a King book signing with a copy of a story King had submitted for publication when he was 11.