Born in the rural district of Bahçe in the province of Osmaniye, Bahçeli attended primary school there. He moved to Istanbul for his secondary education. Bahçeli received his higher education from the scientific academy in Ankara and his doctorate from Gazi University in Ankara. Bahçeli served as a lecturer for economics at Gazi University before entering political life in 1987.

In 1987, Devlet Bahçeli became a member of the board of the Nationalist Task Party (MÇP), which was officially renamed the Nationalist Movement Party (MHP) during a congress on 24 January 1993. Following the death on 5 April 1997 of the founder and leader, Alparslan Türkeş, he became on 6 July 1997 the second chairman of the MHP. From 1999 to 2002, Bahçeli served as a deputy prime minister in the coalition government (DSP-ANAP-MHP) of Bülent Ecevit.

In the 2007 general elections, Devlet Bahçeli led the MHP list in the province of Osmaniye. His parliamentary list polled 44.90% (99,565 votes) and won two of the four provincial seats.

He made his most famous speech in 2009 which is the 40th anniversary of Nationalist Movement Party. The English translation is “When you are writing the number, 2009, there are two zeros. The zero next to 9 is on the left, you erase it, and also get rid of the zero in 20, It will give you 2 and 9. Add then together what would it give you? It would give you 11. You erase both of the zeroes which exist within 2009, what would be left? 29. Now add 11 and 29, it would give you 40, and this is the 40th anniversary of the Nationalist Movement Party.”

In the 2011 general elections, he led the MHP list in the province of Osmaniye. His parliamentary list polled 41.22% (110,708 votes) and won two of the four provincial seats.

In 2015 a Uighur staffed, Turkish owned Chinese restaurant was assaulted by Turkish nationalists; they also attacked the Dutch consulate, mistaking it for the Russian consulate, and assaulted several South Korean tourists, believing them to be Chinese. Devlet Bahçeli said that the attacks by MHP affiliated Turkish youth on South Korean tourists was “understandable”, telling the Turkish news paper Hürriyet that: “What is the difference between a Korean and a Chinese anyway? They both have slitty eyes. Does it make any difference?”

He accused Russia for the Turkish soldiers, who were shot in an accident by Russian fighter planes in 2017. He said; “Russia shoots our soldiers, then disgusts them. This is a mistaken, shameful, international law said to count”.

In the 2018 general elections, he joined with the AKP and Recep Tayyip Erdogan’s presidential campaign.