He replaces Emmanuel Ramazani Shadari, who has been in the post since December 2016.
“This is no surprise for those who are familiar with the management of state affairs,” a presidency source told AFP, without giving any further explanation.
“This is not a disavowal” of Shadari, another source said, citing recent reforms to the statutes of Kabila’s ruling People’s Party for Reconstruction and Democracy (PPRD).
The reforms, published last month, include the abolition of the party secretary general post to allow for a party president, a position many observers expect Kabila himself to assume.
Sakanyi was, until his nomination to the interior ministry job, the PPRD’s secretary general.
The 55-year-old has held several ministries and diplomatic positions including serving as ambassador to Russia and Belgium.
Shadari is one of 16 senior members of the Kabila regime on an EU sanctions list.
The sanctions were first imposed in December 2016. Under the measures, targeted individuals are denied visas to the EU and any assets they may have in the bloc are frozen.
Kabila, 46, who has ruled for 17 years has not yet clearly stated whether he will step aside when DR Congo holds its long-delayed presidential election, currently due to take place in December.