Casambre studied at Claret School of Quezon City where he graduated with first honorable mention.
[9][10] In 2011, Casambre was part of the Philippine national under-13 team that participated in the AFC U13 Festival of Football in Malaysia.
[14] In March 2016, he was among the 35 players called up by the Philippine Football Federation to participate in a training camp with the senior national team, which was preparing for two then upcoming 2018 FIFA World Cup qualification matches.
[15] Casambre impressed Philippine head coach Thomas Dooley during training.
Dooley described the footballer as "awake" and "there", complimented his play using his left foot, noted his minimal mistakes when passing out of the back, and remarked that he was "good in the air".