A member of the local Partido Navoteño, Tiangco served as the representative for the lone district of Navotas prior to his return to the city's mayoralty, preceding and succeeding his brother Toby.

At the same time, his brother, Tobias "Toby" Tiangco, who had founded the party and had just completed his third term as the mayor of Navotas, ran for a position in the House of Representatives.

[citation needed] Housing projects sought to provide relief to those displaced by fires or living in danger zones, and additional pumping stations were established due to the city's flooding problems.

[citation needed] In education, Tiangco's administration launched the NavotaAs Scholarship Program, Kindergarten on Wheels (KOW), and Computer Outreach Learning (COOL).

For this election, Partido Navoteño entered into an alliance with Hugpong ng Pagbabago (HNP), the party of the future Vice President Sara Duterte.

[citation needed] Within the first month of becoming the representative for the Lone District of Navotas, he has already filed House Bills in Congress that will continue to improve the quality of life of Navoteños.

Tiangco has been recognized with:[20][better source needed] Controversy arose in July 2011 when a private organization filed a case with the Ombudsman of the Philippines against many prominent figures in the Navotas government for violating Republic Act 3019 (the Anti-Graft and Corrupt Practices Law).