In your career profile you're able to view your past games.

In your past games you can see a list of players who played in that match.

I am able to Report players for negative behavior, but I am not able to Commend others for good behavior/play.

It's kind of silly that I'm not able to reward someone if I forget to commend someone, hit Exit too quickly, or for some other reason just don't give someone a Commendation immediately after the match ends.

I propose adding "Commend Player" to the list of options that are available when selecting a player's name from the "Game History" section of your career profile.