In 1947 domestic services commenced from Lisbon to Porto as well as from São Tomé to London. Four Douglas DC-4 were purchased in this year, remaining in service until 1960. These were used on routes to Africa and major European destinations including London. The airline was privatised for the first time in 1953, changing from a public service to a public limited company (plc) and began also in 1953, services to Tangier and Casablanca. Lockheed Super Constellation four-engine pressurised airliners, were acquired in late 1955.

Beginning in 1960, TAP Air Portugal launched Rio de Janeiro as its first destination in Brazil, in a jointly-operated air service with Panair do Brasil (1960-1965) and Varig (1965–1967). A route from Lisbon to Goa, a 19-hour flight with five stopovers, was added to the network in the beginning of the 1960s. TAP entered the jet era in July 1962, when three Sud Aviation Caravelle twin-jet airliners were acquired and operated on the airline's most competitive European routes.

In 1966 TAP operated its first solo flight to Brazil, when a company Boeing 707 landed at Galeão Airport in Rio de Janeiro, on 17 June. In 1967, the airline achieved a milestone: it became the first European airline to fly exclusively with jets. In 1969, service to New York City via Santa Maria Island began. Boston was added to the New York service in 1970.

The first of four Boeing 747-200s was received in 1972. TAP began 1974 with 32 aircraft operating to more than 40 destinations on four continents. Following the 25 April 1974 revolution, Portugal was caught up in the wave of nationalisations during the following year and TAP was no exception, thus becoming a state-owned corporation in 1975. The first advanced Boeing 727-200 for European routes were acquired in 1975. Also after the independence of Angola and Mozambique, the important African market decreased tremendously and two Boeing 747s were sold in 1976.

During the 1980s, the fleet of Boeing 707s and 747s was replaced with Lockheed L1011 TriStars in 1983, and Airbus A310s in 1988, on long-haul routes. In 1985 TAP established its charter subsidiary Air Atlantis, providing leisure flights to most European cities, which operated Boeing 707, Boeing 727 and Boeing 737 jets.

In 1989, TAP became a publicly traded company (Sociedade Anónima) and their New York service moved to Newark Liberty International Airport from JFK and in 1991 introduced services to Berlin. By the late 1990s, TAP had expanded its fleet by selling its older Boeing 727s and Boeing 737s, and had replaced them with Airbus A319 (1997) and A320 (1992). In 1993, TAP began flying to Tel Aviv. The TriStars were sold and replaced by Airbus A340s in 1994, giving TAP an Airbus-only fleet.

1996 saw the introduction of services to Boston via Terceira Island, the inauguration of service to Macau and the launch of TAP's website. In 1997, TAP began flying to Punta Cana and Bangkok, though these flights proved uneconomical flights and were discontinued in 1998. A strategic alliance was formed with Swissair in 1997. Part of the agreement would lead to Swissair buying a 34% stake of TAP. Due to financial difficulties, the Swiss company ended up not buying the agreed shares of TAP Air Portugal, unilaterally revoking the partnership agreement which led to unexpected costs for the Portuguese airline in 2000, with the culmination of a legal action taken against Swissair.

Marking a major milestone in its fleet modernization strategy, TAP Air Portugal took delivery of its very first Airbus A321-200 on October 16, 2000. This aircraft, was part of a large-scale fleet renewal program aimed at replacing the airline's aging Boeing 737-300s with more efficient, fly-by-wire Airbus technology. The introduction of the A321 allowed TAP to significantly increase capacity on high-density European routes.

Later, TAP became a member of Star Alliance on 14 March 2005, the same day on which the company celebrated its 60th anniversary. TAP Air Portugal was rebranded as TAP Portugal in February 2005. TAP also ended its code-sharing agreement with Delta Air Lines and began a new agreement with United, as part of its membership in the Star Alliance. In 2006, TAP Air Portugal signed a deal for the acquisition of 99.81% of the Portuguese regional airline Portugália, which had been a primarily competitor to TAP on the domestic and European routes since 1988. TAP received the next phase of its fleet renewal when it took delivery of the first Airbus A330-200 in March 2006. It started scheduled flights to Moscow, Warsaw and Helsinki, in June 2009.

After deciding to outsource its Passenger Service System in 2008, TAP migrated its reservation and inventory systems to the Altéa system managed by Amadeus. In 2010 TAP introduced two new routes to Africa: Marrakesh and Algiers, the latter discontinued in 2017. The launch of these new routes highlighted the carrier airline reinforcement of its growth strategy for Africa, which is an important segment in the network where the airline has continually expanded since 2001. Miami and Porto Alegre were the latest long range routes introduced in 2011.

Since the nationalization of the airline in 1975, there were several attempts to become privately owned, but the deals never went forward to paper. Then, in order to obtain its three-year national bailout, Portugal was forced to sell its interests in several companies, including the state-run airline. Several international operators were drawn by the airline's strategic position, but on 18 October 2012, the Portuguese government announced a sole potential bidder for the privatized national carrier: the South American consortium Synergy Aerospace, owner of Colombian airline Avianca. But agreements did no go as expected and the deal fell through.

On 21 March 2014 the airline announced that it would buy two ATR 42-600s for its subsidiary company, Portugália, replacing the smaller Beechcraft 1900D previously operated by PGA Express. The Portuguese government planned to sell its controlling stake in the flag carrier to one or more large investors in a relaunch of the privatisation in 2014. It intended to sell a 66% stake in the airline.

In May 2015, an over-week-long pilot strike led to the cancellation of around 3,000 TAP Air Portugal flights. Finally after all failed attempts of privatization, a deal was reached in June 2015, the Portuguese government decided to sell the TAP Air Portugal Group, owner of the national air carrier, TAP Air Portugal, to the Atlantic Gateway consortium which took control of 61% of the capital of the Portuguese flag carrier. After the settlement, an ambitious plan came into effect to grow and reflect the airline. It announced new orders, 14 wide-body A330s and 39 narrow-body A320 Family aircraft.

Then, in October 2015, a new left-wing government sought to return majority control of the airline to the state, having signed in February 2016 a deal with the private consortium, to own 50%. On 14 January 2016, TAP Air Portugal announced that the subsidiary Portugália Airlines would be rebranded TAP Express by 27 March 2016, as part of further restructuring measures within the group TAP announced the ceasing of long-haul flights to Panama City, Manaus and Bogota as well as the European connections to Hanover and Zagreb.