In 2014, Byrnes joined the Los Angeles Dodgers as senior vice president of baseball operations. He was recruited by Andrew Friedman, who had just joined the team as president of baseball operations. The new front office was “a force to be reckoned with” according to coverage of the 2014 MLB Winter Meetings. Under Byrnes and the new front office, the Dodgers went on to win the National League pennant, advancing to the World Series in 2017, 2018 and 2020. In 2019, the Dodgers finished the season with the most victories in franchise history (106). The 2020 Dodgers went 43-17 during the COVID-19 shortened regular season and won their first World Series in 32 years.