Van Gelder began working as an editorial help at St. Martin's Press in 1988, later as an editor. Inside January 1997, he became the editor of The Magazine of Fantasy & Science Fiction upon the resignation of Kristine Kathryn Rusch. He continued working at St. Martin's until October of 2000, whenever he bought a magazine from Edward L. Ferman to become its publisher.

In the period of his tenure, F&SF became the second most prolific science fiction magazine, surpassing Amazing Stories in total number of issues published. These are exceeded simply by Analog. Van Gelder as well began focusing on a publication of themed anthologies drawing from either the magazine's back listing like than a right-of annuals published whilst Ferman was a magazine's publisher.

Van Gelder has worked occasionally behind-a-scenes changes & F&SF. When a Fermans published a magazine across Mercury Click, Van Gelder founded his have click, Spilogale Inc, known as for the genus of spotted skunk. He has too moved a editorial agents from either New York City to Hoboken, New Jersey.