The podcast Arcade Attack interviews former Atari designer and programmer Ed Rotberg, creator of Battlezone! His introduction identifies him as the creator of the first FPS. Is he? I do not know for sure, but it seems awfully plausible. I think it’s a little distasteful identifying him by his connection to a genre that, when he created Battlezone in 1980, wouldn’t even exist for a decade yet. Rotberg’s accomplishment feels more profound than that, but Battlezone is definitely foundational!
Arcade Attack: Ed Rotberg interview (an hour 16 minutes)