Martinez began his acting career in 1979 when a talent agency hired him for a television ad. At the time, he was just a personal assistant for his younger brother
William, who was an actor. Soon after, he became a film extra in the 1981 film
Totoo Ba Ang Chismis? followed by a bigger role in the film
Blue Jeans. He took his first
teleserye role as Glenn in the 1980 series
Anna Liza on
GMA Network. Martinez's character, Glenn was the suitor of the titular protagonist, Anna Liza which was portrayed by
Julie Vega. The show lasted until Vega's death in 1985. In 1992, after taking a break from acting to raise his two children with
Anna Lissa "Liezl" Sumilang in the United States, Martinez starred in the romantic drama film
Yakapin Mo Akong Muli, which was a
box office bomb. Martinez then directed his first film
Rosario which was shown at the
2010 Metro Manila Film Festival. Although many praised his direction, he did not receive a
directing nomination. Martinez was part of cast for the 2012 film,
Born to Love You. His next major appearance in a feature film would be in the 2021 adult drama film
The Housemaid, although he also figured in a special role in
Revirginized which starred
Sharon Cuneta. In 2021, he returns to GMA-7 as part of
Las Hermanas. He also played the role of Dr. Richard Smith in
Voltes V: Legacy. Martinez returned again to
ABS-CBN in a villain role in
The Iron Heart as Engr. Priam dela Torre, the leader of the Tatsulok syndicate and the biological father of the protagonist, Apollo, played by
Richard Gutierrez. After
The Iron Heart, he appeared as one of the main casts of
Lavender Fields in 2024. As of 2025, he portrays Mayor Roberto Guerrero in ''
FPJ's Batang Quiapo''. ==Personal life==