Political career
In January 2014, Johnson was selected by party members as a candidate for Edinburgh Southern prior to the 2016 Scottish Parliament election. He was elected to the Scottish Parliament in May 2016, gaining the seat from the Scottish National Party. He became shadow education minister for Scottish Labour in May 2016.
In December 2017, Johnson was promoted to the Shadow Cabinet as Justice Spokesperson. He resigned on 28 May 2019, the day after it was confirmed Scottish Labour had finished fifth in Scotland in the European Parliament elections and lost both its Scottish MEPs. He criticised the Labour Party's "direction and leadership" and noted Labour had finished sixth in Edinburgh. He challenged the party's Brexit policies, stating in his resignation letter he thought Labour should endorse a second referendum and campaign for remaining in the European Union.
In September 2020, Daniel Johnson called for Richard Leonard to resign as Scottish Labour leader, saying "Continuing like this will be disastrous for our party and is why I no longer have confidence in Richard Leonard’s leadership." After Leonard's resignation, Johnson nominated Anas Sarwar in the 2021 Scottish Labour leadership election. In March 2021, he was put back on to the front bench as the Finance Spokesperson for the Scottish Labour Party.
At the 2021 Scottish Parliament election Johnson was supported as a Labour Co-operative candidate for the first time and was re-elected to his seat.
Since 10 April 2023, Johnson has served as Economy, Business and Fair Work spokesperson for the Scottish Labour Party. Since 3 September 2025, Johnson has served as Convenor of the Scottish Parliament's Economy and Fair Work Committee.
Johnson backed the UK Government’s decision to introduce means-testing for the Winter Fuel Payment, voting in the Scottish Parliament against calls to reverse the decision.
At the Scottish Parliament election on 7th May 2026, Johnson was re-elected to represent Edinburgh Southern's new constituency boundary with 42.9% of the vote - an increased vote share of 8.4%. In June 2026, he was appointed Scottish Labour's Shadow Cabinet Secretary for Economy, Energy, Tourism and Transport.
In July 2026, he endorsed Michael Marra in the 2026 Scottish Labour leadership election following the resignation of Anas Sarwar.