Characters of Half-Life – Wikipedia

Gordon Freeman, Ph.D., is the silent protagonist of the Half-Life series, and the playable character in Half-Life, and all games in the Half-Life 2 series. He is a theoretical physicist, and holds a Ph.D. from MIT in that field. At the time of Half-Life, he works at Black Mesa Research Facility, a facility in New Mexico, conducting nuclear and subatomic research.

https://en.wikipedia.org/wiki/Characters_of_Half-Life