Sandoval was born Esther María González in Ponce where she received her primary and secondary education. After graduating from Salinas High School, she attended Colegio Percy de Ponce (Percy College of Ponce) and earned a degree in secretarial sciences.
Sandoval went to work for El Día, a local newspaper in Ponce. She first came into contact with the field of communications when she went to work as a secretary for Emilio Huyke in the radio station WPAB. She auditioned and was named director of a program directed towards a female audience. In 1949, she informed her parents that she wanted to become an artist and she left for San Juan, despite their protests, and went to work for Ángel Ramos' "Radio El Mundo", which later became known as WKAQ. She was given the surname "Sandoval" by the Argentine actress Queca Guerrero. Sandoval landed roles in radionovelas (radio soap operas) and became known in Puerto Rico as "The Queen of the Radio Operas".
In 1954, Sandoval became a pioneer in the island's television when she participated, alongside Mario Pabón and Lucy Boscana, in Puerto Rico's first televised telenovela Ante La Ley which was transmitted through Telemundo. The soap opera caused a national scandal in Puerto Rico because in one scene she kissed her co-star Pabon in the mouth, an act that was totally unheard of in those days.
Sandoval traveled to New York City, where she joined Míriam Colón's theatrical group "El Circulo Dramatico" (The Drama Circuit). Later she founded her own theatrical group and named it "Experimental Hall of Theater". They were located at the Lucerne Hotel of New York. There she produced and starred in Té y Simpatía (Tea and Sympathy) and Dondé esta la Luz? (Where is the Light?). Before returning to Puerto Rico, Sandoval made several presentations in the Teatro Puerto Rico.
In 1959, Sandoval returned to the island and married Ivan Goderich, a Cuban soap opera musical director. They had two daughters, Yara Goderich and Ivonne Goderich. Ivonne would follow her mother's footsteps and become an actress herself. She continued working in soap operas, such as Bodas de Sangre (Blood Wedding), La Novia (The Bride), La Rosa Taluada, Un Tren Travia llamada Deseo, Santa Juana de America and Los Soles Truncos, where she acted alongside her daughter Ivonne and her son-in-law Xavier Cifre. She also lent her voice in the Spanish translation of movies. She was the voiceover of Joan Crawford, Barbara Stanwyck and Rosalind Russell. In 1978, her supporting role in the Telemundo soap opera Cristina Bazán was thoroughly acknowledged, alongside José Luis Rodríguez and Johanna Rosaly. In 1979, she participated alongside Norma Candal, Alicia Moreda, Gladys Rodríguez and Otilio Warrington in Jacobo Morales' movie Dios los Cría (And God Created Them), where she played the role of a prostitute.
According to El Vocero (See reference) Sandoval received many awards and recognitions, including:Best Actress and Best Actress of the Year (1955)
Golden Coqui for Best Actress (1966)
Golden Aqueybana (1968 and 1974)
Selected amongst the most distinguished Puerto Rican women during the celebration of the International Year of the Women
The Golden Coral Award from the Festival of the New Latin Movie in Havana for her role in Díos los Cría
The Legislative Assembly of Puerto Rico approved a life pension for her in 1998 in honor of her valuable contributions to the Puerto Rican theater
The Puerto Rican Institute of Culture dedicated its 46th Festival of the Puerto Rican Film industry to her (1998)
Amongst the movies in which she participated are:Creature from the Haunted Sea (1961)
Thunder Island (1963) - Rena
Traitors of San Angel (1967) - Doña Consuelo
Las Pasiones Infernales (1969)
"Cristina Bazán (1978) TV series - Rosaura Alsina
Dios los Cría (1979) - Old Prostitute
La Otra Mujer (1980) TV series
In the late 1990s, Sandoval suffered from the complications of various health problems such as Alzheimer's disease, chronic diabetes and a cerebral hemorrhage, which left part of her body paralysed. She had been hospitalized at the Antiilas Hospital of Rio Piedras for several years. Her body was cremated on February 10, in accord with her wishes.