was born in Mexico City in 1960. Choosing the path of law studies, he attended the University of Colima where he received his J.D. in 1984, dedicating his graduating paper to “The control of constitutionality of laws in Mexico”.

He was awarded the "Benito Juárez-Peña Colorada" prize as best student of his generation, achieving a 10/10 grade point average. He completed a Masters degree in Constitutional Law and Political Sciences in the Center of Constitutional Studies of Madrid in 1987, where he earned the Annual Award for the “Best Constitutional Law work” for his study on “The Social and Democratic Constitutional State and the Welfare Rights in the Spanish Constitution”. Thanks to his thesis “Social State and Welfare Rights”, Dr. Cossío received his Doctorate Suma Cum Laude in 1988 from the University Complutense of Madrid.

Dr. Cossío started his career as a law Professor in 1983, and has served on the faculty of the Preparatory School of the National Autonomous University of Mexico (UNAM), the Technological Institute of Superior Studies of Monterrey ―Colima Unity― , the Law Department of the National Autonomous University of Mexico (UNAM), the Law Department of the University of Colima, the Pan-American University, the Latin-American Faculty of Social Sciences (FLACSO), and of the Autonomous Technological Institute of Mexico (ITAM), where he was Dean of the Law School from 1995 to 2003.

His professional experience has concurrently been dedicated to teaching, legal research and public service. Although his research and teaching interests focus on constitutional law, he has also carried out research and written widely about other fields of law. He has directed over 38 graduation thesis (J.D., Master’s degree and PHD). Up to this date, Dr. Cossío has given more than 238 speeches, courses, seminars and conferences in various national or foreign Universities (Carlos II University of Madrid, University of Chili, Stanford Law School; Yale Law School; University of Houston, Law Center; University of Texas at Austin; University of California, Berkeley; London School of Economics and Political Science, Center for U.S.-Mexican Studies, University of California y University of Georgia)

Dr. Cossío is a prolific and recognized writer: author of 16 books, he has also contributed to more than 382 articles published in academic journals, law reviews, digests and newspapers.

Dr. Cossío has won distinguishing awards and acknowledgments such as: The National Research Prize in the field of Social Sciences in 1998 granted by the Mexican Academy of Sciences, the 2003 Faculty Merit Medal of “General Lázaro Cárdenas del Río” awarded given by the University of Colima; the National Legal Journalism “José Pagés Llergo 2004” Award given by the Governor of the State of Tabasco and the José Pagés Llergo Foundation. Doctor Cossío is certified National Researcher Level III by the National System of Researchers and has been a member of the American Law Institute since May 2006.

He is currently occupying a seat as one of the eleven Justices of the Mexican Supreme Court, while still teaching Constitutional Law at the ITAM.