He was appointed by President Benigno Aquino III on January 16, 2011, to serve the unexpired term of Chairman Jose Melo.

After that, he was AVP/Legal Affairs Officer of Northern Cement Corporation, a company owned by Eduardo Cojuangco, for 10 years from 1972 to 1982.

He was also a director, corporate secretary and legal counsel of the Eduardo Cojuangco Jr. Group of Companies for various years.

[7] Some quarters had criticized Brillantes fearing that he may not be an objective COMELEC chief, having served popular clients such as former President Joseph Estrada and the Ampatuan family.

He allegedly voiced his fears to President Aquino that Brillantes may favor Senator Francis Escudero or Vice-President Jejomar Binay in the 2016 elections.

[8][9][10] During this time, COMELEC's legal department chief accused him of corruption while Senator Alan Peter Cayetano was vetoing his confirmation.