Edward was a very capable king, but he was also known for for his military aggression against Wales and Scotland. It is said (probably apocryphally) that he promised the conquered Welsh that they would be ruled by someone Welsh born who spoke no English. He then appointed his infant son, born in Wales, as Prince of Wales.
Edward also established Parliament, notable because it included commoners as well as nobles and churchmen.
Modern audiences know Edward best from the movie Braveheart. (Which is painfully unhistorical, but it has the general disposition of Edward correct.)