It was built from 1952 to 1955 to cross the Hudson River at one of its widest points, 25 miles (40 km) north of Midtown Manhattan, from South Nyack to Tarrytown.

A May 10, 1950, editorial in The New York Times suggested that a site in southern Dobbs Ferry or northern Hastings-on-Hudson, where the Hudson narrowed considerably from its three-mile (5 km) width at Tappan Zee, would be a more appropriate site, and suggested that Governor Dewey work with his counterpart, Governor of New Jersey Alfred E. Driscoll, to craft a compromise that would offer Thruway customers a discounted bridge fare at a more southerly crossing.

[8][9][10] A unique aspect of the design of the bridge was that the main span was supported by eight hollow concrete caissons.

Captain Praeger helped develop floating caissons during World War II when the Allied forces needed to create and protect portable harbors for the 1944 invasion of Normandy.

[13] Construction started in March 1952 and the bridge opened to traffic on December 15, 1955, along with a 27-mile (43 km) long section of the New York State Thruway from Suffern to Yonkers.

[16] New York State Governor W. Averell Harriman signed a bill on February 28, 1956, to officially name the structure the Tappan Zee Bridge.

The deteriorating structure bore an average of 138,000 vehicles per day by the end of its life, substantially more traffic than its designed capacity.

Unlike other major bridges in metropolitan New York, the Tappan Zee was designed to last only 50 years due to material shortages during the Korean War at the time of its construction.

[26] The collapse of Minnesota's I-35W Mississippi River bridge in 2007 raised worries about the Tappan Zee's structural integrity.

[27] These concerns, together with traffic overcapacity and increased maintenance costs, escalated the serious discussions already ongoing about replacing the Tappan Zee with a tunnel or a new bridge.

[30] In 2009, the Tappan Zee Bridge was featured on The History Channel "The Crumbling of America" showing the infrastructure crisis in the United States.

[31] Many factors contribute to the precarious infrastructure of the bridge, which has been called "one of the most decrepit and potentially dangerous bridges" in the U.S.[32] Engineering assessments have determined that "everything from steel corrosion to earthquakes to maritime accidents could cause major, perhaps catastrophic, damage to the span," prompting one of the top aides in the New York state governor's office to refer to the Tappan Zee as the “hold-your-breath bridge.”[32] A 2009 state report noted that the bridge was not built with a plan that was "conducive to long-term durability” and that the Tappan Zee’s engineers designed it to be “nonredundant,” meaning that one "critical fracture could make the bridge fail completely because its supports couldn’t transfer the structure’s load to other supports.

[47][48] The old bridge was then demolished in piecemeal fashion in order to minimize impacts on the Hudson River's wildlife and marine traffic.

[3] From 1998 to 2008, more than 25 people committed suicide on the Tappan Zee Bridge, according to the New York State Thruway Authority.

[58] On August 31, 2007, NYSTA officials added four phones – two each on the Rockland and Westchester sides – that connect callers via the National Suicide Prevention Lifeline crisis hotline to counselors at LifeNet or Covenant House.

"[62] Suicides on the Tappan Zee Bridge included those of Scott Douglas on January 6th, 1994 – after murdering his wife, newspaper heiress Anne Scripps – and of Douglas's stepdaughter Anne Morrell Petrillo, who jumped to her death on September 24, 2009.