Ratti graduated from both the Ecole Nationale des Ponts et Chaussees in Paris, France, and the Politecnico di Torino in Italy. He later earned his MPhil and PhD degrees from the Martin Centre at the University of Cambridge, UK. In 2000 he moved to the Massachusetts Institute of Technology (MIT) as a Fulbright fellow, working with Hiroshi Ishii at the MIT Media Lab.
In a 2011 TED talk in Long Beach Ratti outlines the vision of an "architecture that senses and responds." Digital technologies are becoming networked and atomised, hence changing the interaction between humans and the built environment. It is as if our cities, buildings and objects were starting to "talk back to us". In a discussion with architect Peter Cook as part of the Royal College of Art 2011/2012 Architecture Lecture Series in London, Ratti traced back his vision to Michelangelo's "why don't you speak to me" and to the Baroque and Art Nouveau periods.
Ratti's work deals with the built environment of cities – from street grids to plumbing and garbage systems – using new kinds of sensors and hand-held electronics that have transformed the way we can describe and understand cities. Other projects flip this equation – using data gathered from sensors to actually create dazzling new environments. The Copenhagen Wheel developed by MIT Senseable City Lab explores how any bicycle could be transformed into a network-connected e-bike by sampling changing a wheel hub. The project Trash Track uses electronic tracking to better understand and optimise flows of waste through cities. He has also opened a research centre in Singapore as part of an MIT-led initiative on the Future of Urban Mobility.
Ratti’s work has been seminal in the field of intelligent or smart cities. In an article published in Scientific American together with Anthony M. Townsend, however, Ratti contrasts the prevailing technocratic vision of smart cities – highlighting instead the "human face" of urban technologies and their potential in promoting bottom-up social empowerment.
Ratti's designs inventively bridge the digital and the physical. The Digital Water Pavilion at the World Expo 2008 in Zaragoza, developed by CRA-Carlo Ratti Associati design practice, reacts to visitors by having streams of water part to let them through. Its literally fluid architecture was considered by Time Magazine as one of the "Best Inventions of the Year." In CRA's extension of the Trussardi fashion house in Milan's central in Piazza della Scala, developed with botanist Patrick Blanc, a green vertical canopy is suspended on a crystal box to promote new interactions with people on the inside and the outside. An un-built proposal for the 2012 Summer Olympics in London turns a landmark building into a "Cloud" of blinking interactive art.
Several design projects rely on data visualisation. Real Time Rome, which filled an entire pavilion at the 2006 Venice Biennale of Architecture, explored real time dynamics of a city mapped through cellphone data. New York Talk Exchange, exhibited at MoMA in New York City as part of the exhibition "Design and the Elastic Mind," moved further to explore global communication flows together with Saskia Sassen. Several projects from the MIT Senseable City Lab were included in Fast Companys "Best Infographics of 2011." A data analysis and visualisation project resulted in an Op-Ed in The New York Times to redesign the map of the United States.
During the 2013 Milan Design Week ("Salone del Mobile") CRA ventured into product design with a project for Italian furniture manufacturer Cassina, called "Our Universe." At the same venue another project, called "Makr Shakr," explored The Third Industrial Revolution and its effect on creativity and design through the simple process of making a drink.
Ratti curated the "Future Food District" – one of the themed pavilions at Expo 2015 in Milan. In 2017, CRA was part of the team led by developer Lendlease which won the international competition to transform the former area of Milan's Expo 2015 into a district focused on science and innovation (MIND-Milan Innovation District).
