The Sears Tower Skydeck observation deck opened on June 22, 1974 and is located on the 103rd floor of the tower. It is 1,353 feet (412 m) above ground and is one of the most famous tourist attractions in Chicago. Tourists can experience how the building sways on a windy day. They can see far over the plains of Illinois and across Lake Michigan to Indiana, Michigan and Wisconsin on a clear day. It takes about 60 seconds to soar to the top in either of two special, Schindler Group elevators. The Skydeck competes with the John Hancock Center's observation floor a mile and a half away, which is 323 feet (98 m) lower. 1.3 million tourists visit the Skydeck annually.

Willis Tower remains the tallest building in the Americas, and retains the world record when measuring from sidewalk level of the main entrance to the top of the antenna.[citation needed] With a pinnacle height of 1730 feet (527 m), it is the second tallest freestanding structure in the Americas, as it is 86 feet (26 m) shorter than Toronto's CN Tower, and is the only other freestanding structure in the Americas to exceed 1640 feet (500 m) in height. As of July 2009, Willis Tower is the fourth tallest freestanding structure in the world (by pinnacle height), after the Burj Dubai, the CN Tower and the Ostankino Tower.At 1,482.6 feet (451.9 m) tall, including decorative spires, the Petronas Twin Towers in Kuala Lumpur, Malaysia, laid claim to replacing the Sears Tower as the tallest building in the world in 1998. Not everyone agreed, and in the ensuing controversy four different categories of "tallest building" were created. Of these, Petronas was the tallest in one category (height to top of architectural elements, meaning spires but not antennas).At 1,482.6 feet (451.9 m) tall, including decorative spires, the Petronas Twin Towers in Kuala Lumpur, Malaysia, laid claim to replacing the Sears Tower as the tallest building in the world in 1998. Not everyone agreed, and in the ensuing controversy four different categories of "tallest building" were created. Of these, Petronas was the tallest in one category (height to top of architectural elements, meaning spires but not antennas).

In February 2009 the owners announced they are considering a plan to paint the structure silver. The paint would "rebrand" the building and highlight its advances in energy efficiency. The estimated cost is $50 million.

Since 2007 the building owners have been considering building a hotel adjacent to the building on the north side of Jackson between Wacker and Franklin on the site of a plaza that is the entrance to tower's observation deck. The tower's parking garage is beneath the plaza. Building owners say the second building was considered in the original design. City zoning does not permit construction of such a tall tower there.