I'm looking for a Korean boy's name to use in a children's story.  It
would be nice if the name had a meaning like 'peaceful' or 'wise,' but
it is more important that it should be a name fitting for a
round-faced, peaceful and happy little boy--something like the Korean
equivalent of a Marvin or a Gordie.

Hi zzouri,

Since I'm not sure whether you will like any of these names, I'm
posting them as a comment for you to decide. I will post the name
first and the meaning of the name after it.

Bae - Inspiration
Chin - Precious 
Chul - Firm 
Gi - The brave one
Ha-Neul - Sky
Ho - Goodness
Hyun-Ki - Wise 
Hyun-Shik - Clever 
Jin - A jewel
Jin-Ho - Jewel lake
Joo-chan - Praise the Lord
Jung - Righteous
Kwan - Strong
Seung - Successor, Winning
Shin - Faith, Trust
Soo - Excellence 
Sun - Goodness 
Yong - Bravery, Courage
Young - Forever, Prosperity

I personally like Chin, Hyun-Ki and Sun.

If you feel this list is sufficient as an answer, please let me know
and I will post it as an official answer.

Best regards,
Rainbow