Hidalgo is known for his work on economic complexity, relatedness, data visualization, applied artificial intelligence, and digital democracy.

His contributions to the field includes the introduction of methods to measure economic complexity and relatedness, the study of people's perception of A.I., the study of collective memory, and the development of multiple data visualization platforms, including The Observatory of Economic Complexity, DataUSA,[2] DataViva, DataMexico,[3] DataAfrica,[4] and Pantheon, among others.

He is the author of dozens of academic papers in complex systems, networks, and economic development, and has created applications of data science and artificial intelligence to understand urban perception and to explore the idea of augmented democracy.

[5] Hidalgo has authored or co-authored three books The Atlas of Economic Complexity, Why Information Grows,[6] and How Humans Judge Machines.

[7] His work was honored in 2018 with the Lagrange Prize, in 2019 with the Centennial Medal from the University of Concepcion, and in 2011 with the Bicentennial Medial from the Chilean Congress.

Soon after its release the book was highly praised by economists including Paul Romer,[14] who a couple of years later won the Nobel prize for endogenous growth theory, Eric Beinhoecker,[15] the director of Oxford's Institute for New Economic Thinking, and Tim Harford,[16] a popular economics author and regular columnist for The Financial Times.

The OEC was co-authored with Alex Simões, who developed this platform as his master thesis in the Macro Connections group at the MIT Media Lab.

Pantheon helps users explore metadata on globally famous biographies as a mean to understand the process of collective memory and of the role of languages and communication technologies in the production and diffusion of cultural information.

Amy Yu, Kevin Hu, and Cesar Hidalgo developed pantheon at the Macro Connections group at MIT.

DataAfrica makes available data on the health, poverty, agriculture, and climate, of thirteen African countries at the subnational level.

DataMexico is a systematized information platform with more than 13,000 profiles about regional economy, infrastructure, exterior commerce, employment, education, gender equity, inequality, health, and public security in Mexico.

He has since engaged in the creation of civic participation platforms, such as MonProgramme2022 and Brazucracia, designed to collect people's preference over dozens of policy issues.