Main cast

• Jodi Sta. Maria as Maya dela Paz dela Rosa-Lim – At 25, Maya is a simple, idealistic provincial girl who dreams of becoming a flight stewardess but in a twist of events ends up becoming a nanny for a wealthy family in Manila. She took the job in exchange of an educational scholarship from her boss, Richard Lim. She is very family-oriented and will do everything to make her family's life in the province comfortable. She has an innocent charm, yet confident, and has a very positive attitude in life. Later in the series, she marries Richard and together they had twins Sky and Sunshine.
• Richard Yap as Richard "Sir Chief" Lim – He is the owner and president of the famous Lim Aviation Services, an aircraft maintenance repair and overhaul business. Known for being a cold, harsh and strict boss, he has one son and two daughters namely: Luke, Nikki and Abby. A widower of five years since losing his wife Alexandra in a plane crash,^[6] he hires Maya to take care of his youngest daughter after she rescues Abby from an incident at the airport. Maya endearingly calls him "Ser Chief." He later becomes a father again to the twins Sky and Sunshine upon marrying Maya.
• Mutya Orquia as Abigail Ruth "Abby" Lim – The youngest of the three, Abby had difficulty expressing herself when her mother died. Richard has spoiled Abby and she has become overly sensitive when she hears fights and arguments in the family. Richard ultimately decided to have her home schooled because they are afraid of Abby's condition. The Lim family hired many nannies in the past and no one lasted even a week because of Abby's difficult ways. But when Maya saves her from an accident at the airport, Abby finds an instant ally in the simple girl from Mindoro.
• Janella Salvador as Nikki Grace “Nik-Nik” Lim – She is the middle child and the spitting-image of her mother. After the death of her mom, Nikki tries to overcompensate for her loss and tries to take charge of her siblings. She always yearns for her father's attention and at first, she has taken a dislike for Maya, Abby's noisy, new nanny. Eventually, she warms up to Maya. She often speaks in Taglish. Later in the series, she develops a crush on her brother's best friend, Nicolo.
• Jerome Ponce^[7] as Luke Andrew Lim – When his mom died, Luke became the silent and rebellious eldest child. Aloof as he may seem, he cares for the welfare of his sisters but he tries to hide it if he can.
• Elisha Delos Santos as Sunshine Shine D. Lim – The baby daughter of the Lim and Dela Rosa family, and the twin sister of Sky.
• Jeo Aquines as Sky D. Lim – The baby son of the Lim and Dela Rosa family, and the twin brother of Sunshine.

Supporting cast

• Aiza Seguerra as Cristina Rose "Kute" dela Rosa – Maya's sister, Teresita and Arturo's daughter and Cho's mother; called Kute – derived from "Kuya" and "Ate". Together with Jeff, they own the Little Pards Chibugan.
• Sylvia Sanchez as Teresita dela Paz-dela Rosa – Maya and Kute's mother, Mamang's daughter, Arturo's wife and Cho's grandmother.
• Lito Pimentel as Arturo dela Rosa – Maya and Kute's father, Teresita's husband, Mamang's son-in-law and Cho's grandfather.
• Gloria Sevilla as Felicidad "Manang Fe" Marcelo-Alejo – Richard's nanny when he was young and the head maid of the household. Later married to Mang Anastacio.
• Divina Valencia as Conchita "Mamang" dela Paz – Kute and Maya's loving grandmother and Teresita's mother.
• Rosario "Tart" Carlos as Dorina "Doris" Malasig – Sabel's close friend and a maid; later Abby's nanny in the Lim family.
• Viveika Ravanes as Isabel "Sabel" Fortuna-Lumaque – Doris' close friend and a cook/maid in the Lim family. Later married Jerry the Security Guard.
• Joan Marie Bugcat as Yaya Lea – A newly added nanny/ maid for the Lim Family.
• Karen Aiza Alimagno as Magda Dominguez – Kute's childhood best friend.
• JM Ibañez as Pocholo "Cho" Macavinta – Jeff and Kute's son.
• Micah Muñoz as Jose Mari "Joma" Adriano – The driver of the Lim family.
• Nathan Lopez as Emmanuel "Emman" Castro – Maya's friend/roommate.
• Marlo Mortel as Nicolo Angelo "Mallows" Cortez – Luke's best friend and Nikki's love interest. Nikki calls him "Mallows".
• Paul Jake Castillo as Simon Gabriel Corpuz – Maya's childhood friend, who used to court her.
• Shy Carlos as Maria Rosario Jonina "Joni" Quijano – Luke's co-intern at Lim Aviation Services; later became his girlfriend.
• Jeremiah "Bagito" Roxas as Ron-Ron – Bullied Cho at first; later became friends.
• Vandolph Quizon as Ramon Lino "Marcelino" – Jeff's cousin, who also works in the karinderia.
• Kelly Gwayne dela Cruz as Aira Denise Mendoza – Nicolo's best friend.
• Claire Ruiz as Josephine "Joey" Acosta – Luke's friend/ex-girlfriend. Also the former President of West Teatro in Northwest Hills.
• Mai-Mai Adriano as Megan – Nikki's classmate/friend.
• Abigail Francisco Macapagal as Stacy Gutierrez – Nikki's classmate/friend.
• Arvic Tan as Louie – Luke and Nicolo's friend.
• McCoy de Leon as Iñigo Cabanatan – Trouble-maker during high school; later became Luke and Nicolo's friend.
• AJ Muhlach as Amiel Sebastian – Senior transferee in Nikki's school; later belongs to Luke's tropa.

Recurring cast

• Noel Trinidad as Don Roberto Lim – Richard's father and grandfather to the Lim children.
• Marissa Delgado as Doña Esmeralda Lim – Richard's mother and grandmother to the Lim children.
• Carlos "Rusty" Salazar as Mang Anastacio Alejo – Manang Fe's love interest; later became her husband.
• Tom Rodriguez as Jeff "Pards" Macavinta – Kute's friend and Cho's father; he later left the series (following his transfer to GMA-7 for his role on the then-upcoming drama, My Husband's Lover.)
• Maricar Reyes as Rafaella "Rafi" Alcantara – Richard's best friend.
• Assunta de Rossi as Katrina "Ina" Ruiz – Maya's boss who has a crush on Richard.
• Kalila Aguilos as Liza – Richard's former secretary.
• Johan Santos as Wilson de Juan – Maya's classmate.
• Diamond Shen as Jonah – Maya's classmate.
• Robert Ortega as Fred – Richard's assistant that moved and work to another company.
• Ya Chang as Engineer Yamaguchi – Richard's employee.
• Jerico Redrico as Lloyd
• Pinky Amador as Zenaida Belmonte – Maya's teacher.
• Cris Villanueva as Atty. Ryan Molina – Richard's friend and attorney.
• Terence Baylon as Elmer – Driver of a neighboring house near the Lim household. Sabel and Doris have a crush on him.
• Mark Luz as Engineer Gutierrez
• Hazel Faith dela Cruz as Edz Viray – A flight attendant and Maya's friend.
• Chris Bugoy as Bugoy
• Bryce Viray as Lance
• Carla Guevarra as Ms. Pacheco - Maya's instructor of Time Airways.
• Sier Edward Atienza Lao, Jade Gultiano, Pol Aron Casas, Erwin Strydom and Prince Ivan Nacachi as Tropa ni Iñigo – Iñigo's bad influenced friends.
• Bart Guingona as Charles- one of the Board of Directors of LAS.

Guest cast

• Nick Lizaso as Don Julio Demornay
• Sunshine Garcia as Stephanie
• Joyce So as Anna Martinez
• Dionne Monsanto as Teacher Emy – Abby's home-school teacher.
• Jed Montero as Teacher May Anne
• Joy Viado† as Senyang
• Melai Cantiveros as Yaya Gemma
• Karen Leslie Dematera as Gina
• Princess Manzon as Karisa
• Agatha Tapan as Yaya Melinda
• Bianca Saldua as Monica – Maya's friend.
• Cai Cortez as Luisa
• Meg Imperial as Sarah
• Andre Tiangco as Airline Purser
• Jomari Umpa as Pao
• Yanna Asistio as Angge
• John Arcilla as Wedding Priest
• Jose Mari Chan as Wedding Singer
• Bodjie Pascua as Ramon Francisco
• Lollie Mara as Norma Melendez
• Irma Adlawan as Victoria Reyes
• Leo Rialp as Antonio Garcia
• Kazel Kinouchi as Georgina Barrel
• Ketchup Eusebio as Dr. Tim Gonzaga
• Aleck Bovick as Lucinda Quijano – Joni's mother.
• Jon Lucas as Michael
• Jopay Paguia as Thea Lindsay Angeles – Kute's friend.
• Pamu Pamorada as Clarita
• Liza Diño as Mercy Selgado
• Jenny Miller as Betsy
• Katya Santos as Camille
• Art Acuña as Interviewer
• Mark Jayson Bañez as Boris – Pizza Delivery Boy and Doris' love interest.
• Sunshine Cruz as Alexandra "Alex" Lim – Richard's deceased wife and the mother of Luke, Nikki, and Abby. She died in an airplane crash.
• Luis Manzano as Capt. James Ventura Jr. – A pilot who works for Time Airways. He is also the son of the CEO of Time Airways.
• Ina Raymundo as Celeste Madrigal – LAS Former COO and Ralph Madrigal's Wife
• Regine Tolentino as Corrine Celeste – Maya and Richard's wedding planner.
• Edward Mendez as Charlie Ramirez – Rafi's boyfriend.
• Kathryn Bernardo as young Fe
• Daniel Padilla as young Anastacio
• Ping Medina as young Arturo dela Rosa
• Beauty Gonzalez as young Teresita dela Rosa
• Jenine Desiderio as Wedding Singer
• Jose Mari Chan as himself
• Dante Ponce as Don Fernando

Ratings

The drama's pilot episode garnered a 15.2% nationwide rating, considerably high for a 'morning' drama, and dominated its competitor, GMA7's Chef Boy Logro: Kusina Master which got 8.8% according to data released by Kantar Media.^[8] Be Careful with My Heart premiered strongly on July 9, 2012, on the pre-noontime block, and ended in 2014 with a final rating of 19.6%. Be Careful With My Heart's ratings peaked during one of its airings in January 2013, reaching 31.3% nationwide rating, marking the all-time highest rating on daytime Philippine television by any non-sports or non-live show.^[9]