And Johanan begat Azariah, (he it is that executed the priest's office in the temple that Solomon built in Jerusalem:)

Johanan beget Azarias. This is he that executed the priestly office in the house which Solomon built in Jerusalem.

and Johanan begot Azariah (he is it that exercised the priesthood in the house that Solomon built in Jerusalem);

and Johanan begat Azariah, him who acted as priest in the house that Solomon built in Jerusalem.

And Johanan was the father of Azariah, (he was priest in the house which Solomon put up in Jerusalem:)

and Johanan begot Azariah 'he it is that executed the priest's office in the house that Solomon built in Jerusalem':

Johanan conceived Azariah. He is the one who executed the priestly office in the house that Solomon built in Jerusalem.

Johanan - Supposed to be the same as Jehoiada.
Executed the priest's office - Probably this refers to the dignified manner in which Azariah opposed King Uzziah, who wished to invade the priest's office, and offer incense in the temple. See 2-Chronicles 26:17, 2-Chronicles 26:18.

And Johanan begat Azariah, (he [it is] that executed the (b) priest's office in the temple that Solomon built in Jerusalem:)
(b) And valiantly resisted king Uzziah, who would have usurped the priest's office (2-Chronicles 26:17-18).

he it is that executed the priest's office in the temple that Solomon built in Jerusalem--It is doubtful whether the person in favor of whom this testimony is borne be Johanan or Azariah. If the former, he is the same as Jehoiada, who rendered important public services (2Ki. 11:1-20); if the latter, it refers to the worthy and independent part he acted in resisting the unwarrantable encroachments of Uzziah (2-Chronicles 26:17).
in the temple that Solomon built in Jerusalem--described in this particular manner to distinguish it from the second temple, which was in existence at the time when this history was written.

The priest's office - So did all the rest, but it is implied that he did it worthily, he filled his place, and valiantly discharged his office in Uzziah's time. Solomon built - In Solomon's temple; so called to distinguish it from the second temple which was built or in building when these books were written.