He was an abused child. He let himself get overweight and oppressed by life. He had a dead end job as an exterminator.
He had enough. He marched into a U.S. Navy recruitment office because he decided he wanted to be a Navy Seal. He was told he was almost 100lbs overweight and seal training started in some ridiculously short time. So, he lost 100lbs in some ridiculously short time frame and got in.
Seal training literally puts you through hell. Aside from sleep deprivation and crippling physical challenges, you have to swim, at night, in freezing cold ocean water. He couldn't really swim and he was negatively buoyant. He broke his knee cap and hid it from the trainers until it could not be hidden anymore. So, he failed on attempt 1.
He came back for attempt 2, knee still messed, he caught pneumonia, was removed from training, and failed attempt 2.
He came back as soon as possible, still not quite right with the knee, and still not quite right from pneumonia, and passed on attempt 3.
He became an exemplary Navy seal and after a few tours of duty, went to work as a recruitment officer for the seals.
He started running and decided to do an ultra marathon, thinking that it was 100 miles of running over several days, which is was not. It's 100 miles in one big run. At 70 miles his body started to shut down. The bones in his feet were broken. He refuse to fail, so he got up out of his chair and ran 30 more miles with broken feet and failing internal organs.
From that point forward, he has become a trainer to the very wealthy and a motivational speaker, emphasizing that the barriers you place on yourself can be overcome if you put your mind into the right head space.
For people who like to push themselves and achieve, he is a bit of a prophet type figure, as in, when faced with adversity you ask yourself "What Would Goggins Do?" Some people like Tony Robbins, some people like David Goggins. Me, I'm a Goggins type.
His book is a good read