Found on xbox360achievements.com
This achievement must be done in a "Be-A-Pro" season, if you dont want it to take hours, then this is how I did it quickly.
Start off by going to transfers, pick any team to start, it doesn't matter. Once the transfer window comes up, press "Y" to search for players, choose detailed, and change the "Min Ovr." to 85. A list of about 6 pages should come up, YOU WANT TO PUT ALL OF THE FOLLOWING PLAYERS ON SYDNEY FC:
IKER Casillas - 91 (Spain)
Javier Zanetti - 86 (Argentina)
Lucio - 87 (Brazil)
Alessandro Nesta - 88 (Italy)
Phillip Lahm - 85 (Germany)
Carles Puyol - 88 (Spain)
Cristiano Ronaldo - 89 (Portugal)
Franck Ribery - 88 (France)
Kaka - 90 (Brazil)
Zlatan Ibrahimovic - 89 (Sweden)
Francesco Totti - 86 (Italy)
Keep the same order as above.
Then go into squads, and put these all as starters on Sydney Fc AND USE THE 4-1-2-1-2 FORMATION.
(Main Menu ===> Manage Team ===> Team Management)
Then choose any player off the starters and make them captain, I would suggest "Christiano Ronaldo" as he is by far the best player.
But, if you choose someone else, make sure to also make sure to make the capital of their national country!
Once done, start a new "Be A Pro" season with Sydney Fc, for your player select who ever you made captain.
From there on in, simulate every single one of your matches, and this along with "Club God" should unlock along the way of the 4 seasons. I managed to get Club God after 2 seasons.
At the end of the 4 seasons, you MUST WIN the Be-A-Pro world cup thingy to unlock "Living Legend". So I suggest that you play these matches, just to be sure, because many people have lost out here by simming their Be-A-Pro cup matches.
It works perfectly ;)