The House Teaching of St. Thomas, located in San Jose, Costa Rica, in 1829 was awarded the degree of Bachelor of Civil Law.
In 1820 he starred in a serious conflict with the Subordinate Political Head of Costa Rica Juan Manuel de Cañas -Trujillo, who objected to adopt a position Osejo a speech at the swearing-acts the Constitution of Cádiz in Carthage .
Policy had an outstanding performance in Costa Rica in the early years of independence and was one of the most important figures of groups sympathetic to a Republican and adversaban annexation to Mexican Empire of Iturbide.
He was elected as Member Provincial Congress met in constituent Carthage on 3 March 1823 and 8th of that month decided the separation of Costa Rica the Mexican Empire.
His rule was brief, as the 29 March a military coup led by the monarchist leader Joaquin Oreamuno and Muñoz of Trinidad deposed authorities and broke the constitutional order.
After the fall of the monarchy, and after some incidents, Rafael Francisco Osejo returned in July 1823 to take his seat in the Constituent Assembly, but was canceled in August his credentials as a deputy and the following month he was imprisoned for have suspicions that members of the council had been in conturbenio with monarchists coup.
In August 1833 he was appointed State specific counter and in October of that year he was elected as a deputy judge of the Supreme Court of Costa Rica.