Albert Barnes Commentary 1 Chronicles 27:32-34

"Also Jonathan, David`s uncle, was a counsellor, a man of understanding, and a scribe: and Jehiel the son of Hachmoni was with the king`s sons: And Ahithophel was the king`s counsellor: and Hushai the Archite was the king`s friend: and after Ahithophel was Jehoiada the son of Benaiah, and Abiathar: and the captain of the king`s host was Joab." — 1 Chronicles 27:32-34 (ASV)

This is a supplemental list of some of David's chief officers not mentioned previously. The list cannot be from a very late part of David’s reign, as it contains the name of Ahithophel, who killed himself during Absalom’s rebellion (2 Samuel 17:23).

Was the king’s companion (1 Chronicles 27:33). This refers to the “king’s friend,” as in 1 Kings 4:5. (Compare to 2 Samuel 16:17.)

After Ahithophel (1 Chronicles 27:34). That is, next in counsel to Ahithophel: inferior to him, but superior to all others.