From 1998 till 2001, he was a People's Deputy of Ukraine for People's Movement of Ukraine parliamentary faction, surrendering his deputy mandate early.[9] In 2002, Lavrynovych was elected to parliament on the Our Ukraine party list, but refused to be registered. In May 2002, Lavrynovych was appointed as Justice Minister in the Kinakh Government.[8] In the First Yanukovych Government (2002–2005) he was also Minister of Justice of Ukraine.[9] After a short intermezzo as Deputy Chairman of the Board of "Ukrnafta" (2005–2006) Lavrynovych returned to national politics in August 2006 as First Deputy Minister of the Cabinet of Ministers of Ukraine in the Second Yanukovych Government.[9] But he soon moved to the post Minister of Justice of Ukraine again (from 1 November 2006 till 18 December 2007).[9] In the 2007 parliamentary election he was elected Deputy of Ukraine for Party of Regions.[9] From the dismissal of Arseniy Yatsenyuk till the election of Volodymyr Lytvyn as Chairman of the Verkhovna Rada, Oleksandr Lavrynovych assumed the position as acting chairman from November 12, 2008[10] till December 9, 2008.[11][12] The Verkhovna Rada refused to include in its agenda an issue concerning dismissal of its first Vice Speaker Lavrynovych on November 17, 2009.[13] Starting 11 March 2010, Lavrynovych became Justice Minister again.[8] On 2 July, he was elected as member of the Supreme Council of Justice of Ukraine.[14]Olena Lukash replaced Lavrynovych as Justice Minister 2 days later.[15]
On April 10, 2014, Oleksandr Lavrynovych resigned from his position with Supreme Council of Justice. Since that time he is acting as legal expert and holds the position with the Board of Institute for Legal Society, a Non-governmental organization.
On 13 July 2015, the Ukrainian Prosecutor General's Office announced that Lavrynovych was suspected of embezzling public funds worth more than 8.5 million Hryvnia.[16] It said these funds were used to finance foreign law firm Skadden, Arps, Slate, Meagher & Flom (USA) that helped to win the court case in the European Court of Human Rights by the State of Ukraine and at the same time "to conceal evidence of criminal violations of the law by Ukrainian state law enforcement agencies and the courts" during the 2011 trial of Yulia Tymoshenko.[16]
In March 2016, Ukrainian court released Lavrynovych from any restrictions of Prosecutor's office.