[12] Messerschmidt was convicted in 2002, receiving a suspended sentence of prison for 14 days for violating the Danish hate speech law by publishing material that attempted to link Islamic societies to rape, violence and forced marriages.

[13][14] Between 2003 and 2005 he was assistant to the Danish People's Party's European parliamentarian Mogens Camre Before taking his seat in the European Parliament, Messerschmidt was a member of the Danish Parliament, the Folketing from 8 February 2005, having won his seat with 3,812 personal votes,[15] and being re-elected in 2007, this time getting 11,466 votes.

For a short period of time in 2007, Messerschmidt left the Danish People's Party due to accusations of showing Nazi sympathies, as he according to the tabloid newspaper B.T.

Arne Ullum and journalist Jacob Heinel Jensen which both were punished with 10 daily fines of 500 kr.

[19] Messerschmidt has been associated with the counter-jihad movement, and has been described as a proponent of the ideology associated with the blog Gates of Vienna[20] for which he gave an interview at a 2009 conference in Washington, D.C.[21] He has in counterjihad-associated interviews "blamed left-wing parties and governments for capitulating to the Muslim ‘invasion’,"[20] and stated that the European Union would be overrun by a civil war with Muslims in 20 years.

In 2019, Messerschmidt was elected to the Folketing with 7,554 personal votes, and in 2020 became vice chairman of the DF, replacing Søren Espersen.

Ekstra Bladet was nominated for a European Press Prize for investigative reporting in 2017 for their coverage of the scandal.