This is not exactly how Liam Clancey did it as he had a higher upper range to his vocals, however,
for a mid range vocalist these chord in this repetitive chord three same one off pattern works decently.
Capo 1
Intro 
C Am G C  
C Am C G  
C Am C G  
C Am G C 
   C       Am         C         G
Of all the money that e'er I?ve seen
     C        Am      C    G         
I've spent it in good company
    C       Am        C        G
And all the harm that ere I?ve done
  C     Am     G        C  
Alas it was to none but me
    C        Am       C       G
And all I've done for want of wit
   C      Am    C       G
To memory now I can't recall
   C       Am     C       G
So fill to me the parting glass
     C         Am     G        C
Good night and joy be with you all  
Repeat intro
   C       Am     C       G
Oh fill to me the parting glass
    C       Am          C       G
And drink a health what ere befalls
  C      Am       G      C
I gently rise and softly call
    C         Am     G        C
Goodnight and joy be with you all
   C       Am            C      G
Of all the comrades that e'er I had
        C     Am     C      G
They're sorry for my going away
    C       Am               C      G
And all the sweethearts that e'er I had
       C       Am       G      C
They'd wish me one more day to stay
    C        Am     C     G
But since it fell unto my lot
     C        Am       C          G
That I should rise and you should not
  C      Am       G      C
I gently rise and softly call
     C         Am     G        C
Good night and joy be with you all  
C         Am        C      G
A man may drink and not be drunk
  C       Am        C      G
A man may fight and not be slain
  C       Am      G      C
A man may court a pretty girl
    C          Am       G    C  
And perhaps be welcomed back again
Repeat intro
    C        Am     C       G
But since it has so ordered been
     C       Am         C       G
By a time to rise and a time to fall
     C       Am     C       G
Come fill to me the parting glass
     C         Am     G        C
Good night and joy be with you all  
     Am        C      G        C
Good night and joy be with you all