D&D General Highest level PC you've achieved.

[Zardnaar]

Overall, my primary 1E character was my highest, but I technically didn't start with the character (it was one of the DMs, who gifted it to me so I could play in the current adventure). He had run it from level 1/1 Druid/Thief to about level 5/7 when I took it over, then played it for about 5 years until she was level 36 Thief (Druid capped out in 1E, but I don't remember at what level).

Assuming you don't count that one, my highest level character was a 4E Warlord I took to level 30 in a Dark Sun campaign. The DM basically ran us through the novels as the protagonists.

Other editions:
2E: capped levels for an elf fighter/mage, but I don't remember what the level limit was (mage was mid-teens)
3E: highest only got to level 15 before it collapsed under itself
5E: got a dwarf cleric up to level 18, which was a ton of fun

12 fighter 15 mage 2E iirc. Optionally higher based on ability scores or double xp iirc.

 

[Arnie_Wan_Kenobi]

4E: Finished Scales of War at Level 30 (albeit there was one point we jumped a few levels to wrap everything up), and I took three months off when I got a fellowship. That's the only campaign I've been in that never fizzled out or faded away. We're CLOSE to finishing 5E Tomb of Annihilation, at level 9. That's been once a month, three hour session for seven years. (I took some time off to finish a Masters in there, too.)