Julia started her career in showbiz as a child product endorser with a milk product, particularly Nido. It has been also reported that she auditioned for a slot in "Eat Bulaga" but she was not accepted there. She then auditioned in ABS-CBN children gag show "Goin' Bulilit" and there her star started to shine.

           But before her stint in "Goin' Bulilit", Julia was featured in the drama series "Hiram". She portrayed the role of the young Stephanie Borromeo which was later portrayed by [[Anne Curtis]]. Julia had a long run with the gag show "Goin' Bulilit" in the span of 2004 up to 2008. She used her real name in the show and it was only until the year 2008 that she used the name Julia Montes.

       After her stint in "Goin' Bulilit" in 2008, Julia was featured in the soap drama "Maalaala Mo Kaya" in ABS-CBN in the episode "Card". She portrayed the role of Abby and many critics lauded her performance in that episode. She would then appear in the same soap drama in the following year with the episodes "Diary" and "Lubid".

It was also later in the year 2008 that she starred in two hit drama series titled "I Love Betty La Fea" and "Ligaw Na Bulaklak". She portrayed the "young" roles of the main characters Daniella Valencia and Janet respectively. She also had a cameo role in "Katorse" towards the end of the show wherein she played as Nelie, the flower girl in the wedding.

       She was then included in the cast of the television series titled "Gimik 2010" which was a part of the Kapamilya Network's "Your Song" weekly series. It was also an adaptation of the 90's series titled "Gimik". Julia portrays the role of Clara.

"Mara Clara" was then the biggest bread in Julia Montes' showbiz career and Mara was her biggest role ever. The series was a remake of an old TV soap opera with the same title which was top billed by Judy Ann Santos and Gladys Reyes. Julia portrayed the role of Clara who was the bad girl in the story and Julia portrayed it well. The other role - the good girl Mara - was portrayed by Kathryn Bernardo. Julia and Kathryn became the hottest new stars in TV with their superb portrayal of their roles in "Mara Clara". In fact, the popularity series prompted Star Cinema t make a movie version of the series and it was a very big hit in the box office charts.

         The success of "Mara Clara" catapulted Julia's career to the limelight of Philippine show business. She was then invited to join "ASAP", a talent - variety show and she is still in the show as of this writing (June 2012). Julia also joined the cast of "Mara Clara" in "Laugh Out Loud" - a comedy gag show that aired every Saturday nights in ABS-CBN.

           She also appeared twice in ABS-CBN's fantasy-drama anthology titled "Wansapanataym" with the episodes "Three In One" and "Unli-Gift Box" as Trina Santa Romindo and Star De Jesus respectively. Julia and the cast of "Mara Clara" again joined forces to realize the teen drama anthology in ABS-CBN titled "Growing Up". They were joined by other teen casts of Gimik 2010 and other teen stars.

            Julia would then portray the role of Katerina Alcantara Montenegro in [[Walang Hanggan]] opposite hunk [[Coco Martin]]. The series casts very high figures in the TV ratings chart all over the Philippines. In fact,It is the only prime time drama garnered a 44.7 by June 25 and the last episodes garnered 45.45%.