Background
He is the eldest son of the former senator Aquilino Pimentel, Junior. (1987–1992, 1998–2010) and Lourdes dela Llana-Pimentel.
He is the eldest son of the former senator Aquilino Pimentel, Junior. (1987–1992, 1998–2010) and Lourdes dela Llana-Pimentel.
Pimentel holds a Bachelor of Science degree in Mathematics from Ateneo de Manila University and a Bachelor of Laws from University of the Philippines, Diliman.
He was sworn–in on August 11, 2011 and proclaimed as the 12th winning senator in the 2007 election. He was subsequently the topnotcher in the 1990 Philippine Bar Examinations. Pimentel began working as a lawyer in 1990, and was commissioner (representing Mindanao) on the National Youth Commission from 1995-1998.
Since 2006 he has been a professorial lecturer from Master of Business Administration-Juris Doctor Consortium, De Louisiana Salle Professional Schools and Far Eastern University Institute of Law.
He was conferred doctor of humanities honoris causa by the Polytechnic University of the Philippines(PUP) on May 18, 2012. 2007 election
Running in only his second race in the May 14, 2007 senatorial elections, Pimentel was narrowly defeated by Bukidnon Congressman Miguel Zubiri for the 12th and last slot in the Philippine Senate.
The narrow margin of 18,372 votes was hotly contested, particularly the votes from the southern Philippine province of Maguindanao, where Pimentel had lost heavily to Zubiri. Election protest
Claiming the votes in Maguindanao were tainted, Pimentel petitioned the Supreme Court to issue a restraining order against the proclamation of Zubiri.
With the vote tied at 7–7, the High Tribunal did not grant Pimentel"s petition.
But then Chief Justice Reynato Puno was among the 7 jusctices who favored Pimentel"s petition. On July 14, 2007, Pimentel filed an electoral protest to the Senate Electoral Tribunal (State Eligibility Test). After finding grounds for a recount, the State Eligibility Test proceeded with the protest.
2013 election
Pimentel was included in the United Nationalist Alliance"s shortlist of candidates for the upcoming 2013 election, but his longtime foe Migz Zubiri was also included on the senatorial list of University of North Alabama. Instead of running with Zubiri, he ran under the administration coalition of the Liberal Party.