[1] He gained significant popularity when he participated in the first season of Tawag ng Tanghalan of the noontime television show It's Showtime, a singing competition broadcast on ABS-CBN, and becoming its first runner-up.
His father, Wilfredo Mangubat, is a pastor of a Christian church in Santo Tomas, Batangas, whereas his mother, Crisanta (Santi) Marbella-Mangubat, is a housewife and a former City Municipal Administrative Officer.
Due in part to the popularity of some of his covers in his YouTube channel, he was featured on several television programs such as CgeTV In da Loop[17] and ASAP, both broadcast on ABS-CBN.
[8] The album was introduced on shows like Rise and Shine broadcast on UNTV[16] and Tambalan sa DZRH News Television.
[6] On August 16, 2016, Mangubat participated in the third Quarter of Tawag ng Tanghalan (TNT) sa Showtime, a singing competition broadcast on ABS-CBN.
Rey Valera, one of the judges, commented that Mangubat's voice seemed to fit better on the rock ballad genre and that it sounded "imported".
Garnering an average score of 94.4% from the judges, Mangubat won against the two other contenders vying to challenge the current defending winner.
On his second performance, he sang "Flying Without Wings" by Westlife for which he garnered an average score of 95.6% eventually beating the defending champion.
Valera commented that Mangubat got the right image, moves, energy, intelligence, and talent, but cast some doubt on whether he has grown wiser and luckier on his second attempt.
[22] On his third day, however, he made an apparent mistake with the abridged lyrics of the song "All Or Nothing" by O-Town which disappointed the judges prompting Valera to call the performance "palpak" (failure).
[28] Mangubat performed "Ikaw" by Yeng Constantino on the second day for his first attempt to enter the Top 5, but he lost to Froilan Canlas after garnering only 75.35% combined average score from the judges and text votes.
[30] On March 11, 2017, Mangubat competed with the five other Grand Finalists who were able to get their slots to perform at the "Huling Tapatan" at the Resorts World Manila.
[2][3] Despite failing to enter the semi-finals on his first attempt in Tawag ng Tanghalan, Mangubat continued to be popular and had been requested by fans to be featured on several music venues.
[33][34][35] Intermittently since 2016, Mangubat, together with his three-member vocal group Dreamzone (includes Shane Tarun and Jun Sisa), has been regularly performing on various cruise ships around Asia.
Mangubat was also invited twice on the sixth year of ASOP (A Song of Praise) Music Festival (UNTV) to serve as an interpreter.
He further commented on his performance of "Flying Without Wings" in Tawag ng Tanghalan that "Sam immediately commanded the stage, captivating the audience with his powerful and smooth voice, easily doing the job of the four boys of Westlife all by himself".
[46] Upon reviewing the grandfinalists of Tawag ng Tanghalan, Nestor Torre of Philippine Daily Inquirer noted that Mangubat was a standout and has the combination of looks, talent, and charisma.