Albert Barnes Commentary 2 Kings 25:22

"And as for the people that were left in the land of Judah, whom Nebuchadnezzar king of Babylon had left, even over them he made Gedaliah the son of Ahikam, the son of Shaphan, governor." — 2 Kings 25:22 (ASV)

We may be allowed to conjecture that Jeremiah, in gratitude for Ahikam’s service to him (Jeremiah 26:24), recommended his son Gedaliah to Nebuzaradan, and through him to Nebuchadnezzar, for the office of governor.