Canavan opposes same-sex marriage. In 2017, when Cory Bernardi moved a motion to ban abortion on gender grounds, Canavan was one of ten elected representatives who voted for the motion, which was defeated with 36 votes against. As the Resources Minister, he has been strongly supportive of the Carmichael coal mine and has questioned the importance of climate change mitigation. In contrast to former South Australian state premier Jay Weatherill, Canavan is dismissive of the Hornsdale Power Reserve having referred to it as: "the Kim Kardashian of the energy world". He is known as one of the climate "doubters" in the Morrison government, and denied that climate change caused the catastrophic 2019–20 Australian bushfire season. In response to a protest in November 2018 where high school students walked out of class to protest the Australian government's inaction on climate change, the Senator responded "I want kids to be at school to learn about how you build a mine, how you do geology, how you drill for oil and gas". He also stated "The best thing you'll learn about going to a protest is how to join the dole queue."
Canavan's mother had registered him as an "Italian resident abroad" with the Italian consulate in Brisbane in 2006. Canavan stated that he had been unaware of this until his mother had informed him of it following the resignation of two Greens senators over their dual citizenship. The government took the view that he was not in breach of the Constitution, as the registration had not been made with his knowledge or consent. Initially, Canavan accepted that he had Italian citizenship. He then renounced it, effective 8 August 2017. On the same day, on a government motion with all-party support, the Senate resolved to refer the matters of Senators Ludlam, Waters and Canavan to the High Court as Court of Disputed Returns. The Attorney-General indicated that the Commonwealth would argue, in favour of Cavanan, that s 44 requires a personal acknowledgement of the connection, which had not occurred. Canavan spoke in support of the referral, while stating that he did not believe he was in breach of s 44, and said that he would not be voting in the Senate until his position was determined by the Court. Later, four other members of the federal parliament were referred to the High Court, which heard the seven cases together. In the High Court, government lawyers argued for Canavan and others that s 44 requires some personal acknowledgement of another citizenship, which had not occurred; in its judgment on 27 October 2017, the Court rejected this interpretation of the sub-section. For Canavan, it was argued in addition that his registration as an "Italian resident abroad" in 2006 had been incorrect in supposing that he was an Italian citizen and that, although a change in Italian citizenship law when he had been two years old could appear to have conferred Italian citizenship upon him, it could not be shown to have done so. The Court accepted these points and held that Canavan had never been a citizen of Italy; accordingly, he had been validly elected.