Craig is a native Californian who lived most of his early life in San Diego. He received his PhD from Scripps Institution of Oceanography, at the University of California, San Diego, in 1989, where he began his long-standing interest in deep-sea hydrothermal vents. He conducted post-doctoral work with Steve Giovannoni at Oregon State University before taking his first academic position at the University of Delaware. Craig currently holds a joint professorial appointment between the University of Waikato, in New Zealand, and the University of Delaware in the United States. He is a microbial ecologist with more than 25 years of research focused on two primary areas – studying microbial life in extreme environments – during which he has participated in over 29 deep-sea expeditions to the hydrothermal vents including many dives in research submersibles. His recent work on extreme environments now includes 13 seasons in Antarctica to study microbial life in the Dry Valleys, thought to be the coldest driest place on earth, and in the high temperature soils on the summit of Mt. Erebus. His other scientific passion lies in understanding the causes of blooms of harmful algae in aquatic systems. He is currently the Deputy Director for the New Zealand Antarctic Research Institute (NZARI) the primary funding agency for Antarctic research in New Zealand.