According to sources, the other agencies involved were incumbent Cheil Vietnam, AVC Edelman, GroupM and digital marketing agency Maxxus (no relation to GroupM's Maxus).
The appointment takes effect on 1 June.
According to Kate Bayona-Garcia, head of digital and innovations, Leo Burnett Vietnam, the win will see the agency doubling its team to serve the Samsung account.
Currently, Leo Burnett handles work for Samsung across Southeast Asia, Australia and Taiwan.