Coach

Coach is one of the four playable survivors in Left 4 Dead 2. Coach was a high-school football instructor for a well playing team, but he suffered a nasty knee injury. Ironically, he's now a health teacher pushing 40 years old, but he's gone to seed since his collegiate glory days. The zombie apocalypse makes him wish he'd watched his own fitness more closely. Faliszek says Coach has "a great hatred for a few of the zombies—the Witch in particular," but naturally, he wouldn't explain why.

Quotes
"See: Coach/Quotes"

Trivia

 * Many players assume that Coach is Bill's Left 4 Dead 2 counterpart.
 * Many people relate Coach with the character Uncle Phil from the TV show The Fresh Prince of Bel-Air. He also resembles Bubb Rubb of "whistletips" fame. Coach also slightly resembles rapper Rick Ross.
 * Coach appears to have a slight speech impediment, occasionally dropping his R's and G's. This is probably due to Southern dialect.
 * He may also be somewhat religious as he usually makes comments referring to the Bible and stating the last time he saw his grandmother, she asked if he was still a praying man.
 * Bill and Coach have many things in common. According to their back-stories, both Bill and Coach have knee injuries. They also are the oldest in their group, and have a dislike for climbing stairs. On top of that, they both have a different physical disadvantage. Bill's disadvantage is that he's older than anyone out of the two groups. On the other hand, Coach's disadvatage is that he is overweight, preventing him doing similar things to Bill. (Note how Bill is quite healthy for his age).
 * "Though I walk through the valley of the shadow of death" was originally a quote from the Bible, Psalms 23:4.
 * In an issue of PC Gamer, the original concepts of the Coach can be seen, including a skinny coach, a white coach, and a coach in football shoulder pads used as armor. He also holds a bow and arrows (depicted in the gallery below).
 * Coach's default weapon may be the AK-47 probably because he is seen holding one in every campaign poster, except for Dead Center and Hard Rain. His default melee weapon may be the Chainsaw, as well.
 * If you notice, Coach is wearing the same type of sports fingerless gloves similar to the ones worn by Francis.
 * Coach appears to hold a pistol with only one hand when his health is lower than 40 HP.
 * Coach's shirt is not the same as his actual shirt as for now in the updated Swamp Fever poster. It looks alot more like it's previous version, though it's blue part looks more purple.
 * Coach was the second survivor (first being Rochelle) to have a different look in game from the poster. He still had his blue and yellow shirt on Swamp Fever poster at Comic-Con while in game he was wearing a yellow-purple shirt.
 * It seems from the new trailer he highly enjoys chocolate, as he is seen eating a bar of it and Nick teases him with the idea of a chocolate helicopter to lead him fast up stairs (This could be a reference to Doc Louis from the game series Punch Out, who resembles Coach rather closely.)
 * So far, Coach is the only survivor without a known name.