Marita Camacho Quiros was born in San Ramon, Alajuela, Costa Rica on 10 March 1911, the seventh daughter of Salustio Camacho Munoz and Zeneida Quiros Quiros. She was baptized on 21 June 1911. Her second-cousin, Daniel Oduber Quiros (1921–1991), was the President of Costa Rica from 1974 to 1978.
She married Francisco Orlich Bolmarcich in Naranjo, Alajuela, Costa Rica on 16 April 1932. The couple adopted two children: Francisco Jose, and Mauricio Orlich Camacho.
Her husband was the 34th president of Costa Rica from 1962 to 1966. She was the first woman to participate alongside her husband in the handover ceremony on 8 May 1962, before the first ladies did not have direct participation in the handover ceremony. As First Lady, she actively worked for children. She also promoted a Costa Rican Social Security project that built houses for poor families.
She was responsible for accompanying her husband on several trips abroad and in welcoming the President of the United States John F. Kennedy and the other Presidents of Central America and Panama in 1963, as well as a visit to the Vatican to His Holiness John XXIII. In 1962, she toured several European countries, including Spain, where she visited Francisco Franco, the leader of the nationalist forces during the Spanish civil war and head of state from 1939 to 1975. On 30 June 1964, President Lyndon B. Johnson of the United States delivered remarks of welcome to Francisco Orlich and Marita Camacho, when they visited America for official state business. Afterwards, President Johnson took them to a dance party.
She was widowed in 1969.
Her second cousin Adela Monge Quiros (23 January 1907 – 4 January 2015) lived to be 107 years, 346 days.
As of her 109th birthday in 2020, she has five grandchildren, and four great-grandchildren.
She became the oldest known living person in Costa Rica upon the death of 111-year-old Claudia Soto Saborio on 10 December 2020.
In April 2022, she voted in the Costa Rican presidential election runoff.
She became the oldest living person in the world notable for reasons other than longevity, following the death of 111-year-old Stanislaw Kowalski on 5 April 2022.
As of October 2021, she is one of ten living Costa Ricans who receives a presidential pension.