Lawwell will join other existing board members including chairman Karl-Heinz Rummenigge of Bayern Munich, AC Milan's Umberto Gandini, Edwin van der Sar of Ajax and Arsenal's representative Ivan Gazidis.
The European Club Association is the sole, independent body directly representing football clubs at European level.
Lawwell told Celtic's official website: "This is a tremendous honour and a role which I very much look forward to undertaking.
"European football is an ever-changing landscape and from the perspective of Celtic, it is vital that we ensure we are at the heart of the action and at the centre of discussions regarding the development of the game.
"As we look to the future, I look forward to representing Celtic, Scottish clubs and the other clubs in Europe to ensure that the voice of these clubs and their supporters is heard."