He started his television career in 1996 through ABS-CBN's youth oriented show Gimik and was paired with singer-actress Jolina Magdangal.
He was also chosen to be one of the lead casts of soap opera Esperanza and miniseries Sa Sandaling Kailangan Mo Ako.
[2] He was paired with Magdangal once again and they become the protagonists of soap opera Labs Ko Si Babe, the first Philippine romantic-comedy series.
After Labs Ko si Babe ended in 2000, he became part of the trio named Whattamen together with his real life best friends Dominic Ochoa and Rico Yan.
Agustin won his first TV and film acting awards for his performance as Filipino boxing champion Manny Pacquiao in the episode of "Boxing Gloves" in Magpakailanman in 2004's 1st Golden Screen Entertainment TV Awards, and as a disturbed psycho Lemuel in the horror-thriller Kutob in 2005's 31st Metro Manila Film Festival.
In 2017, Agustin briefly returned with an exclusive contract to GMA Network three years later via his drama series Kambal, Karibal (originally titled as Santa Santita).
Agustin attended International School for Culinary Arts and Hotel Management, he joint ventured with the restaurant entrepreneurs and called it Sumo Sam, which specializes in Japanese-American modern cuisine.