In the Chinese version of Yakuza 0, Lao Gui has a different appearance modeled after and voiced by Hong Kong actor Sam Lee.

The Japanese release of Yakuza 0 had a purchasable DLC pack that would give both Kiryu and Majima access to Walkmans that could play classic songs from Japan associated with the 1980s, or songs from past entries in the series.

The UI, beat maps, and camera transitions of Yakuza 0's disco minigame appear as leftover data in the files for Yakuza Kiwami.

In the Visionary Fortune-Teller sub-story of Yakuza 0, a fortune teller quizzes Kiryu about what will happen in his future, with all of her predictions actually happening to him at different points in the Yakuza series. She tells Kiryu he would go on to have a child he loves who he needs to put a price on (referencing the events of the first Yakuza game), that he would have eight children (referencing the orphans he would adopt in Yakuza 3), driving a taxi in Fukuoka (referencing Yakuza 5), and that he would take the blame for someone else's crime (again referencing the first Yakuza game.)

Kan Ogita, Haruka's dance teacher in Yakuza 5 (considered a relatively obscure character) would later have a brief cameo in the prequel game Yakuza 0, where he was one of the opponents Kiryu could face in the Dance Battle minigames.

The Japanese PlayStation 3 version of the game contained an exclusive pre-order bonus: an issue of the magazine "Hot Dog Press" with Kiryu Kazuma and Majima Goro on the cover. Of the contents in the magazine, it reveals some minor details about the character Akira Nishikiyama including the following:

• He works for a rehabilitation program providing an honest living to yakuza members, as well as scouting for hostesses and addressing restaurant troubles.
• He spends an hour washing his hair each day.
• He often uses his Tojo Clan pin to get out of paying parking tickets.