After Diokno enrolled in law at UST, his studies were interrupted by the outbreak of World War II. When the war was over, he was granted a special dispensation by the Supreme Court of the Philippines and was allowed to take the Philippine Bar Examination despite having never completed a law degree. He topped the 1944 bar exam together with a 24 year old future ally named Jovito Salonga with a score of 95.3, the highest since Jose L. Quintos of Bulacan set the record in 1903. As a reward he took a solo vacation in the United States, where he would frequently call Carmen ""Nena"" Icasiano, a commerce student from Bulacan studying at Far Eastern University. They met in 1946 at a dinner party hosted by a future politician named Arsenio Lacson, and eventually got married in a Manila church immediately after Diokno returned from his shortened trip. He quickly proposed to her after he found out on the telephone that she was sick and had missed seeing him.