While in High School, Kilifi played center but later found his calling as a prop as he matured into his bruising size, earning High School All American honors.

Kilifi would go on to play for the Seattle Saracens at the Senior Club level and earned his way into the USA Rugby pathway. In 2013, Kilifi made his Men's Eagles debut in a win against Georgia.

Kilifi was named to the USA Rugby 2015 Rugby World Cup team, playing three matches. In 2016, Kilifi signed with the Sacramento Express of PRO Rugby North America.