Alumnus of Har Etzion, Rav Yishai has been a Ram at Yeshivat Har Etzion since 2016. The son of an alumnus, Rav Jeselson learned in Yeshiva Tichonit Makor Chaim before entering Har Etzion. Rav Jeselson completed his Hesder army service in the Nachal Brigade, and then attained semikha from the rabbanut. He has since attained a degree in Special Education from Herzog College and has also qualified for City Rabbinate. Rav Jeselson currently teaches an Israeli Shiur Bet shiur.