During World War II, his father became a member of the Polish resistance movement; he was captured by the Gestapo, and subsequently died in the Sachsenhausen concentration camp.

Disturbed by the invasion, and by the brutal crushing of the parallel Polish 1970 protests, in 1972, Kukliński sent a letter to the US embassy in Bonn describing himself as an army officer from a Communist country and requesting a secret meeting.

The documents described Moscow's strategic plans regarding the use of nuclear weapons, technical data about the T-72 tank and 9K31 Strela-1 missiles, the whereabouts of Soviet anti-aircraft bases in Poland and East Germany, the methods used by the Soviets to avoid spy satellite detection of their military hardware, plans for the imposition of martial law in Poland, and many other matters.

[7] Facing imminent danger of discovery from a denunciation by a secret Communist collaborator known only by his alias "Prorok",[8] Kukliński, his wife and two sons were spirited out of Poland by the CIA shortly before the imposition of martial law in December 1981.

When asked whether Jaruzelski was a hero or a traitor, Kukliński replied: My view has been consistently that in Poland there existed a real chance to avoid both Soviet intervention and martial law.

Had he, together with Stanislaw Kania, proved capable of greater dignity and strength, had they honestly adhered to the existing social agreements, instead of knuckling under to Moscow, present-day Poland would undoubtedly look completely different.

According to President Carter's NSA, Zbigniew Brzeziński, "Kukliński's information permitted us to make counterplans to disrupt command-and-control facilities rather than only relying on a massive counterattack on forward positions, which would have hit Poland.

[15] When all charges were dropped against Kukliński in 1997, the left-leaning Trybuna lamented that "Colonel Ryszard Kukliński—a spy, deserter, and traitor—has been turned into a model of virtue and a national hero of the rightists.

[18] Also, the matter of Kukliński's sons' deaths is unclear and they may have been part of a protection program; besides, according to Wieczorkiewicz, such revenge on a defector's family would be quite unusual for Soviet intelligence.

[18] Kukliński is buried in the row of honour in the Powązki Military Cemetery in Warsaw, and he has been given honorary citizenship of several Polish cities, including Kraków and Gdańsk.

The Polish political group Centrum (at the time headed by Zbigniew Religa) requested in 2004 that the President of Poland posthumously promote Kukliński to the rank of general.