Bryson, an Ulster Protestant from Donaghadee, was born in 1990 to David and Louise Bryson. He first came to public attention as the vice-chair of the North Down Somme Society, in which role he led complaints that the Royal British Legion were excluding the society from participation in Remembrance Day events due to its alleged loyalist paramilitary links. He became a "youth cohesion worker", and in December 2010 helped found the Community Partnership political party. He stood for the party in Bangor West at the Northern Ireland local elections, 2011, but took only 167 votes and was not elected.
In 2011, Bryson was active in a campaign against North Down Borough Council's allocation of Peace III funding, through which he met with Martin McGuinness. Early in 2012, he was convicted of carrying a concealed weapon, which he stated was to protect himself from drug dealers angered by his role as a community activist. Later in the year, he published The First Shades of God, a book which argued that churches should adapt to popular culture.
At the end of 2012, Bryson became a leading figure in the Belfast City Hall flag protests, serving for a time as chair of the Ulster People's Forum. In this role he has co-operated closely with Willie Frazer. The two briefly split in February 2013, before joining forces again. Several times, he was a member of the audience of the Stephen Nolan Show when the flags protest was the subject of heated debate and was challenged by Nolan to explain his position regarding the street protests. Bryson compared the treatment of the flag-protesters to the treatment of Jews by the Germans during the Nazi era. In a Twitter post on 25 February 2013, Bryson stated that he would not view the loyalist paramilitary group, the Ulster Volunteer Force (UVF), as terrorists.
He was taken into custody in Bangor on 28 February 2013 for questioning in connection with public order offences, after reportedly being on the run for 24 hours. He was arrested at the home of his friend Pastor Mark Gordon, who claimed that the arrest had been arranged with police. Gordon objected to how the arrest was portrayed in the media, stating that Bryson was in an unlocked bedroom rather than hiding in a locked attic. Whilst on the run Bryson posted a video on the internet calling the Police Service of Northern Ireland (PSNI) "fascists" and mocking their inability to apprehend him. Bryson was one of three protest leaders arrested, the others being Frazer and former British National Party funder Jim Dowson, with Dowson the only one of the three to be granted bail. In early March Bryson was charged with six matters relating to the protests, in response to which he briefly went on hunger strike. The hunger strike was reported to have lasted only half a day, and Bryson's request for an Indian takeaway led fellow loyalist inmates to label him as "Jamie Biryani". On 11 March he was moved from the main complex for remand prisoners in Maghaberry Prison to the separate building containing segregated loyalist wings, Bush House. He had asked to be transferred for his own safety due to threats he had allegedly received from dissident republican inmates, although the prison said that dissident republican prisoners were held outside the main complex in a third part of the prison, Roe House.
Bryson was bailed on 27 March with a number of conditions attached to the bail, including the requirement to sign in daily at Newtownards PSNI station, a curfew, a ban on using a mobile phone, a ban of attending protests or making public speeches and a ban on entering Belfast city centre.
In December 2013 the Sunday World and Sunday Life printed photos of Bryson claiming Jobseeker's Allowance before going to work at a taxi office. Bryson originally threatened to take the paper to court if it ran with the story. He later stated he was only volunteering with the taxi company.
In March 2015 Bryson was found guilty of taking part in unlawful public processions and obstructing traffic due to his role in the protests. He was convicted of four charges brought against him after the court was shown CCTV footage of Bryson protesting in the middle of a road.
Bryson has repeatedly described loyalist paramilitary groups such as the UVF (classified by the British government as a 'terrorist organisation') as "patriots". He posted a message on Twitter in April 2013 in which he claimed "loyalists were not terrorists. The IRA were the terrorists." He then added: "I would not view the UVF as terrorists no." On 29 December 2013, Bryson posted a blog in which he described loyalist paramilitary groups as "patriots" who "responded to the threat of terrorism". Bryson has also referred to the UVF as 'God's Army.'
Bryson is also reported to have struck up a friendship with a leading loyalist paramilitary, David McConnell. McConnell was convicted for drugs offences in March 2014 and has been reported by the Sunday World as being the "UVF's second in command in east Belfast". Bryson posted on his blog that both he and McConnell attended parliament buildings together at Stormont (leading to complaints from First Minister and deputy First Minister Peter Robinson and Martin McGuinness). Pictures surfaced on social media sites of Bryson posing with replica guns alongside McConnell. McConnell also posted a commendatory comment regarding Bryson to social networks in the run-up to Bryson standing for election.
A video appeared on YouTube and other social media outlets that appeared to show Bryson cheering and punching the air as the front window of a house in the Catholic Short Strand was smashed during the return leg of a loyalist parade in January 2013. He has never denied this allegation.
Bryson initially put himself forward for the European elections in 2014 as an independent candidate but failed to raise the funds (£5,000) for the deposit necessary for him to stand. Bryson was believed to have raised only £165, and although he said (in a statement he posted to his Facebook account) that he would use the money raised to fund his candidacy for the subsequent local elections, he pulled out of those elections too, citing personal reasons (believed to have been the forthcoming birth of his child). In response to Bryson running for the European elections, the creators of parody social network site LAD started to raise money in a crowd-funding campaign for a fictional rival candidate to Bryson (a gorilla called Koko). The crowd-funding campaign for Koko was claimed by those behind it to have raised more money (£410) than Bryson raised through his fund-raising.
In 2015, Bryson made a number of allegations concerning the sale of loans and properties by the National Asset Management Agency on his blog. This culminated in him giving evidence to the Northern Ireland Assembly's Finance Committee, in which he accused the First Minister of Northern Ireland, Peter Robinson, of corruption.
In August 2016 Bryson was accused of leaking the name of his source in the NAMA revelations An accusation he strongly denied. The leak of the information regarding Daithí McKay, resulted in the MLA resigning his seat.
On 12 January 2017 the Belfast Telegraph reported the allegation that "Jamie Bryson is set to be arrested by police over allegations that Sinn Fein "coached" him before he gave evidence to Stormont's Nama inquiry". Bryson refused to cooperate with the investigation and refused to provide information sought by police, citing journalist privileges, in an article on his blog.
An association football fan, Bryson dressed up to act as the official mascot of the Northern Ireland football team in November 2012, for its match against Azerbaijan, just shortly before the start of his involvement in the flag protests.
Bryson is an amateur footballer who, as of 2013, played for Northern Amateur Football League side 1st Bangor Old Boys F.C. In April 2013 his bail conditions were relaxed so that he could play for the club in their evening kick-off matches. Bryson subsequently signed for East Belfast F.C..