[1][3] Obiena attended Chiang Kai Shek College, a Chinese Filipino school for his secondary education, and later entered the University of Santo Tomas for his undergraduate studies.

[9] Unable to qualify for regional meets, he decided to return to pole vaulting when he was in his last years in high school, in a bid to secure a college scholarship.

[14] On July 20, 2014, at the PATAFA weekly relays held at the PhilSports Football and Athletics Stadium, Obiena broke the national record for pole vault by registering 5.01 meters.

[15] Obiena won a gold medal in the 2016 Philippine National Games Finals in Lingayen, Pangasinan after breaking a new personal record (5.47 meters), despite problems with a broken pole.

[citation needed] Obiena won gold in the men's pole vault event at the 2019 Summer Universiade[16] setting a new national record of 5.76 meters.

He secured a berth in the 2020 Summer Olympics by surpassing the qualifying standard by making a 5.81 meters height in a tournament in Chiara, Italy on September 3, 2019.

[citation needed] The COVID-19 pandemic caused the postponement of the Olympics and travel restrictions imposed by countries in response to the health crisis posed logistical issues to Obiena's preparations.

[18] Competing in the 2020 Summer Olympics in Tokyo, Obiena managed to advance to the final of the pole vault competition but failed to make the podium.

[20] This record was later broken on July 25, 2022, when Obiena lifted his best vault all the way to 5.94 meters at the 2022 World Athletics Championships in Eugene, Oregon, United States.

[21] In June 2023, Obiena cleared 6 meters for the first time at the Sparebanken Vest Bergen Jump Challenge in Norway also resetting the Asian record.

[29] In November 2021, the Philippine Athletics Track and Field Association (PATAFA) publicly escalated an accounting dispute involving late payments to Obiena's coach, Vitaly Petrov.

[30][31] Philippine Senators quickly came to Obiena's defense, calling unproven accusations "harassment" against an athlete considered a national treasure and passing a motion to recall the budget of the PSC.