Mass Effect's morality system handles "Good" vs. "Evil" in terms of two independent ratings of "Paragon" and "Renegade". It is very possible for a hero who is primarily Paragon to also have earned some Renegade points along the way, though this does not typically detract from his Paragon score.
However, there are (with the exception of some bugs) a finite number of opportunities to increase your score in either of these aspects. Also, a choice to increase one usually means passing up a potential increase of the other.
So, this leaves me wondering out of curiosity: Are there enough morality-based decisions in each game for a player to max out both Paragon and Renegade scales on the same character? If so, do the game mechanics really allow for this?
Best Answer
There are ways to max both paragon and renegade in ME1 and ME2 if you use the glitches described on the wiki page. There are multiple ways to do so in both games. In ME1, you can also legitimately gain the paragon/renegade skill ranks as your skills carry over in a new game+ and there are points in the story where you automatically rank up in those skills.
Outside of exploits, its impossible to max both paragon and renegade in ME2 or 3, but you can max the skills in ME1 via new game +.
Currently, there are no known ways to max both in ME3, but it becomes less necessary as in ME3 your total rep can contribute to speech unlock checks rather than individual levels.