Levi, who was contracted until the end of 2017, has agreed to an additional year while Cogger, who was contracted until the end of 2016 has agreed to an additional two.
“Both Danny and Jack are important to the Knights’ future success and are a part of our plan to develop and retain our best young players,” Director of Football Michael Hagan said.
19-year-old Levi made his NRL debut this season in Round 15 and has gone on to play six games while also playing in the NYC and NSW Cup sides.
“We are excited to have someone like Danny, with his talent and potential, sign long term with the Club,” interim coach Danny Buderus said.
“We have seen how Danny has handled playing at NRL level this year and we are glad he’ll be here for at least the next three years.”