She studied at St James College in Quezon City for her primary education and finished high school at the University of Santo Tomas High School in Manila.
On April 20, 2008, Locsin organized a gift-giving to the less fortunate children in Payatas, Quezon City and gave poor children food, clothing and other basic needs.
It was her birthday gift supported by her sponsors.
Her performance garnered her several accolades including the Star Award for Movies for Movie Actress of the Year, the Gawad PASADO Award for Pinakapasadong Aktres, and a nomination for best actress at the FAMAS Awards.
She reunited with John Lloyd Cruz in the romantic comedy film Unofficially Yours in 2012 and then starred, together with Dingdong Dantes and Angelica Panganiban in the drama film One More Try, Star Cinema's entry to the 2012 Metro Manila Film Festival.
She came to prominence for her television roles as Alwina in the 2004 fantasy-themed television series Mulawin and as the superheroine Darna in the TV adaptation of the Mars Ravelo comics.
Locsin was a contract artist of GMA Network up to early 2007 until she transferred to its rival network, ABS-CBN.Also, she starred in the drama film Mano Po III: My Love and in the horror film Sigaw which were both entries to the 2004 Metro Manila Film Festival.In 2005, Locsin with Richard Gutierrez starred in the romantic film Let the Love Begin, released under GMA Films.Locsin reunited with Gutierrez in the romantic drama film The Promise in 2007 where their roles were considered more mature than the previous films they both starred in.She had also produced her own film entitled Angels, which was shown in theaters on April 2007.However, her guesting eventually turned into a regular stint. Locsin's first film appearance was in 2000 via Ping Lacson Supercop, wherein she played the role of a young Robina Gokongwei.