In the game, Justine Jacobs appears as a black man, he is probably a male with African-American heritage. Typically and according to this New York Times article, Black male in America have an average height of 69.1 inches or 5’9. However, we do not think that Jacob falls into this same height range as he actually appears to be a bit smaller when scaled to other characters.
Assuming that the events in the game is set in an American area, observing Justine in this [Breakneck City COMPLETE PLAYTHROUGH NO COMMENTARY Youtube Video] gave us an idea that Justine is a bit shorter compared to most of the male enemies he fight. He is around 2 or 3 inch shorter than most of the male characters. This gives us a hint that Justine may actually fall a bit lower to the average African-American height. Note that despite the other character enemies in the game not being black, this scaling should still be pretty accurate since in the U.S.A, the total height average for all Americans and African-Americans is pretty identical (5’9).
Therefore as a conclusion, we will give Justine Jacobs an estimated height of around 5 feet and 7.5 inches.
Breakneck City COMPLETE PLAYTHROUGH NO COMMENTARY Youtube Video