Yang is a native of Suwon and had been a star taekwondo athlete in elementary school but his PE teacher suggested that he try basketball as he was taller than his peers.

[6] The first two seasons were largely unspectacular as Yang played regularly, averaging 25 to 30 minutes, but was overshadowed by fellow 2007 draftees Ham Ji-hoon and Kim Tae-sul.

He was given the moniker mu-rok (무록), a shortened colloquialism for "no record", referring to the fact that he was a behind-the-scenes player who did the "dirty work" defending the post but had no impressive statistics to show for it.

In April 2009, Yang enlisted for mandatory military service and was assigned to the Korea Armed Forces Athletic Corps's Sangmu team after completing basic training.

[8] During his time at Sangmu, he was given the chance to play in a more offensive role and posted his best statistic in scoring to date, averaging 16.1 points in 9 games, in the 2009–10 KBL Winter League.

The 2011–12 Championship-winning team was soon split up as Kim was traded to Jeonju KCC Egis while Park, Lee and Oh all enlisted for mandatory military one after another.

[12] During Game 3, he scored 13 points, 5 rebounds and 5 assists, most of which were recorded during the fourth quarter and while nursing two injured fingers in his dominant hand.

During the quarterfinals in the 2020-21 playoffs, they were dubbed "Defense Kings" after holding back a Busan KT Sonicboom team which had some of the league's most prolific offensive players.

Living up to his reputation as a "man of the playoffs", Yang scored 15 points in Game 1 of the quarter-final series against Daegu KOGAS Pegasus.

[23] At the 2009 FIBA Asia Championship, he had his best individual tournament to date and helped the Koreans to a seventh-place finish while averaging a 12 points and 4.9 rebounds per game.