Kamiński was born on 25 September 1965 in Sochaczew. He served as deputy to the Sejm of the 3rd, 4th, 5th, 7th and 8th term.
He graduated from the Faculty of History of the University of Warsaw and was an active member of the Independent Students’ Association. As a representative of opposition student organisations, Kamiński was involved in one of the Round Table subgroups. He co-founded the “Pamiętamy” (We Remember) Foundation working to honour and keep alive the memory the Cursed Soldiers. In 1993, he founded and then presided over the Republican League Association. In 1997, he was elected deputy, representing the Solidarity Electoral Action (AWS) coalition.
In 2001 and 2005 he held a parliamentary seat representing the Law and Justice (PiS) party in the Warsaw constituency. In the years 2001–2002, he was the vice-president of the Right Alliance party, then joined the Law and Justice party, where – between 2004 and 2006 – he served as president of the Warsaw region. In Kazimierz Marcinkiewicz’s government, he worked as Secretary of State under the Chancellery of the Prime Minister. Kamiński resigned from his parliamentary seat on 5 July 2006. On 6 July 2006, he received nomination for the position of the plenipotentiary for the organisation of the Central Anti-Corruption Bureau (CBA). On 3 August 2006, Prime Minister Jarosław Kaczyński appointed him as head of the newly established Central Anti-Corruption Bureau. On 13 October 2009, Donald Tusk dismissed him from his post. In January 2011, he returned to the Law and Justice party. In 2011 elections, he was re-elected as deputy to the Sejm. On 26 November 2011, Kamiński was elected Vice-Chairman of the party by the Law and Justice’s political council. In 2015, he was once again elected as deputy, representing PiS.
In 2010, president Lech Kaczyński presented him with the Commander’s Cross of the Order of Polonia Restituta.
Since 2015, he has served as minister – member of the Council of Ministers, Special Services Coordinator.