At the time of his retirement, Koronios was the unofficial all-time stats leader of the Greek Basket League, since the 1986–87 season in points scored, with 7,080, in assists, with 1,264, in steals, with 583, in free throws made, with 2,020, and in three pointers made, with 828.

[1] In total, Koronios appeared in 448 games in the top-tier level league of Greek basketball.

[1] Some of his Greek League career records were eventually broken by Nikos Boudouris, Dimitris Diamantidis,[2] and Vassilis Spanoulis.

In the summer of 2007, he was appointed as the new head coach of AEK Athens, but he decided to resign, "for personal reasons", on 25 October.

He was later appointed as the new head coach of AEK, following the departure of Minas Gekos from that position, in January 2011.