According to The Baltimore Sun, Ekwonna pleaded guilty to the charges on Tuesday, before US Attorney Robert Hur.
Ekwonna, 29, was also sentenced to five years of supervised release after his prison term.
Two counts of sex trafficking of a minor were levelled against the former police officer. It was revealed that Ekwonna exchanged more than 250 text messages and social media messages with two girls, ages 14 and 15, and paid both for sex.
Ekwonna was charged in April 2017 with soliciting sex from a 15-year-old girl in Glen Burnie and then robbing her at gunpoint.