The intro to Fallout 1 shows an in-universe news program depicting events from the US annexation of Canada, which happened between 2072 and 2077. The dev is saying the male protagonist from Fallout 4 is one of the soldiers in the footage executing a Canadian insurgent.
So at some point the male protag was in the US army sometime around 2072. The bombs fall in 2077, he's frozen, then he's awoken in 2287.
The intro to Fallout 1 shows an in-universe news program depicting events from the US annexation of Canada, which happened between 2072 and 2077. The dev is saying the male protagonist from Fallout 4 is one of the soldiers in the footage executing a Canadian insurgent.
So at some point the male protag was in the US army sometime around 2072. The bombs fall in 2077, he's frozen, then he's awoken in 2287.
That Canadian insurgent? Yaroslav Hunka.