Loriod was born in Houilles, Paris, France. She studied at the Paris Conservatoire and became one of Olivier Messiaen's most avid pupils. She also studied with Marcel Ciampi. At the age of 25, she was appointed professor at the Conservatoire National Supérieur de Musique de Paris. She went on to become a nationally-acclaimed recording artist and concert pianist, and premiered most of Messiaen's works for the piano, starting in the 1940s. Messiaen said that he was able to indulge in "the greatest eccentricities", when writing for piano, knowing that they would be mastered by Loriod. Both she and her sister Jeanne often performed as the soloists in his Turangalîla-Symphonie. Loriod also orchestrated part of Messiaen's final orchestral work, Concert à quatre.
In 1961, Loriod married Olivier Messiaen following the death of his first wife, Claire Delbos. She is generally considered to be the most important interpreter of Messiaen's piano works. In her later years, she and Messiaen acted as mentors to the pianist Pierre-Laurent Aimard, who has since become a great champion of the works of Messiaen.