It's the first redevelopment since Terminal 5's construction in 1993 and includes two dozen new high-end retail and dining options.
It also features sleek interior design upgrades that give parts of the terminal the feel of a comfy lounge or trendy nightclub.
Mayor Rahm Emanuel says Friday that the redesign reflects Chicago's "distinct style and spirit" and will place the city at the "center of the global tourism conversation."
Among the new offerings are a spa, a local gourmet deli called The Goddess & Grocer and a restaurant overseen by celebrity chef Rick Bayless.
And coming soon are an Emporio Armani and a Michael Kors shop.