He became secretary of the Municipality of Guayaquil under Mayor Assad Bucaram (his brother's father in law), of the populist party Concentración de Fuerzas Populares.

León Roldós did not enjoy a good relationship with President Hurtado, having opposed the assumption of the private external debt by the government (known as the "sucretización"), among other economic policies.

On 31 October 1994, León Roldós was elected rector of the University of Guayaquil, and served two terms, which were acknowledged to have revitalized this institution.

León Roldos ran for president in 1992 under the banner of the Socialist Party of Ecuador and in a second attempt in 2002 as an independent; he received then 15.4% of the vote and barely missed the runoff election.

In the 2006 Ecuadorian general election he ran again, this time in a ticket of the alliance of "Ethics and Democracy Network" (Red Etica y Democrática) and of the Democratic Left Party.