Growing up in Nevşehir, a small province in Central Anatolia, Çatlı was familiar with the views of the far right MHP, and Turkish ultra-nationalists, which were strong in this area.
Çatlı was responsible, along with Haluk Kırcı and several other MHP members, for the 9 October 1978 Bahçelievler Massacre in which seven university students, members of the Workers Party of Turkey (TIP), were murdered.
He is also said to have helped Mehmet Ali Ağca murder the left-wing newspaper editor Abdi İpekçi on 1 January 1979, in Istanbul, and helped Ağca escape from an Istanbul military prison, in 1979. According to investigative journalist Lucy Komisar, Abdullah Çatlı "reportedly helped organize Ağca's escape from an Istanbul military prison, and some have suggested Çatlı was even involved in the 1981 Pope's assassination attempt". In 1998 the magazine Monde diplomatique alleged that Abdullah Çatlı had organized the assassination attempt "in exchange for the sum of 3 million German mark" for the Grey Wolves. In 1985 in Rome, Çatlı declared to a judge "that he had been contacted by the BND, the German intelligence agency, promised him a nice sum of money if he implicated the Russian and Bulgarian services in the assassination attempt against the Pope".
Çatlı then went to France, where, under the alias of Hasan Kurtoğlu, he planned a series of attacks (18 in France and the rest in Yugoslavia, Lebanon, Germany, Canada, USA and Austria) on Armenian interests and on the ASALA, with help from MİT including the blowing up of the Armenian monument at Alfortville on 3 May 1984 and the attempted murder of activist Ara Toranian.
According to founding Alparslan Türkeş, the founder of the Grey Wolves and the Nationalist Action Party (MHP) , "Çatlı has co-operated in the frame of a secret service working for the well-being of the state".
Turkish intelligence service (MIT) paid Çatlı in heroin, and he was eventually arrested in Paris on 24 October 1984 for drug trafficking. He was sentenced to seven years imprisonment and in 1988 he was handed over to Switzerland, where he was also wanted on charges of drug dealing. However, he escaped in March 1990 with the assistance of old friends from the Grey Wolves. He returned to Turkey, and was then recruited by the police for "special missions" while he was officially being sought by the Turkish authorities for murder.
Turkish Prime Minister Tansu Çiller declared on 4 October 1993: "We know the list of businessmen and artists subjected to racketeering by the PKK and we shall be bringing their members to account." Beginning on 14 January 1994, almost a hundred people were kidnapped by commandos wearing uniforms and travelling in police vehicles and then killed somewhere along the road from Ankara to Istanbul. Çatlı demanded money from people who were on "Çiller’s list", promising to get their names removed. One of his victims, Behçet Cantürk, was to pay ten million dollars, to which casino king Ömer Lütfü Topal added a further seventeen million. However, after receiving the money, he then went on to have them kidnapped and killed, and sometimes tortured beforehand.
According to Mehmet Eymür, a team led by Çatlı was responsible for the 1995 deaths of Iranian spies Lazım Esmaeili and Askar Simitko. Çatlı's fingerprint was also allegedly found on the drum of one of the machine guns used to assassinate Ömer Lütfü Topal. In 1996 Çatlı twice kidnapped Mehmet Ali Yaprak.