Wallis was born in Bettws, Bridgend, the son of Daryl Hamilton Wallis, a computer forensics expert. He was a member of Pencoed council, representing the Hendre ward, until 2018, when he was replaced because of non-attendance at meetings. He later stated that he had resigned from the council by letter, but the council had not received the letter. He said that his reason for resigning was that he had relocated to Cowbridge, where he joined the town council. Wallis is one of the owners of a company called Fields Holdings Limited, the parent company of Action Direct Limited, a former claims management company of which Wallis was a director in 2011 when the Ministry of Justice banned it from taking on any further employment claims work, following an investigation into the company's conduct. In July 2010, a Freedom of Information request was made to Bridgend County Borough Council asking how many complaints or referrals to Trading Standards had been made about a Field House associated company Rapid Data Recovery Ltd, which returned the response that between 1 January 2009 and mid-2010, 37 complaints had been received, a figure which included associated companies. In January 2020, after being elected to Parliament, Wallis threatened to take legal action against BCBC over the matter under the Freedom of Information Act.. A Buzzfeed investigation in January 2020 found that Wallis had been a co-owner of a 'sugar daddy' dating website, "which offered students financial relationships with wealthy 'sponsors'". Although Wallis initially denied links to the company, Buzzfeed found that he had been a director and shareholder of the site's parent company. The Labour MP Jess Phillips called for Wallis to have the Conservative whip removed. Since the election, Wallis has reportedly quit as director of at least seven companies. Wallis has a doctorate in astrobiology from the University of Cardiff, supervised by Chandra Wickramasinghe and focusing on evidence for cometary panspermia. The degree was awarded in 2014, though Wickramasinghe had left the university in 2011.
