Does Kingdom Hearts on PS2 Have Co-op Multiplayer?

No. The original Kingdom Hearts (PS2, 2002) and Kingdom Hearts II (PS2, 2005) are **strictly single-player** experiences. You control Sora exclusively; Donald and Goofy are AI companions.

There is **no local split-screen, no online co-op, and no drop-in/drop-out** in any PS2 Kingdom Hearts title.

Co-op in the Series (Later Entries)

• Kingdom Hearts: Birth by Sleep (PSP, 2010): **Mirage Arena** — Up to 3 players ad-hoc (local Wi-Fi) for co-op missions and versus. Main story is solo.
• Kingdom Hearts Re:coded (DS, 2010): **Avatar Menu** — StreetPass/Tag Mode for profile sharing, not real-time co-op.
• Kingdom Hearts 3D: Dream Drop Distance (3DS, 2012): **Flick Rush** — Local 2-player card battle minigame.
• Kingdom Hearts III (PS4/Xbox, 2019): **No co-op.** Single-player only.
• Kingdom Hearts: Melody of Memory (2020): **Co-op / VS** — 2-player local (shared screen) and online versus in rhythm stages.

If you want to play KH with a friend, **Birth by Sleep (PSP/Vita/PS3/PS4/PC via 1.5+2.5 ReMIX) Mirage Arena** is the only substantial co-op mode in the series.