"We had a very positive step forward in Iraq today," Kerry said.
"These were critical positions to be filled, in order to assist with the organising effort with respect to (the Islamic State group). So we're very pleased."
Kerry was speaking from Boston, where he is meeting for two days of talks with a top Chinese official, State Councillor Yang Jiechi.
Khaled al-Obaidi of the Iraqi parliament's Sunni Arab Itihad al-Quwa al-Wataniyah bloc was voted defence minister, and Mohammed al-Ghabban of the Shiite Badr bloc was picked for the interior post.
Kerry's talks with Yang began informally at dinner yesterday and come as Washington and Beijing wrestle with a number of bilateral differences and global issues.
"There are many issues that China and the United States are cooperating on, even as we have some differences that we try to manage effectively," Kerry said.
Kerry said North Korea, Afghanistan, Iran, the Ebola virus, climate change and the Islamic State group were among the topics of talks.
Yang said "much progress" had been made in the relationship between the United States and China.
