He underwent another minor knee surgery almost immediately upon joining the club, with the goal of returning to full fitness in time for a club debut in round 1, 2019. By mid January he had resumed limited training including running at high pace and remained on schedule for the season's opening round. As part of his reduced training program, Lynch missed most of the club's match-simulation drills and both of Richmond's official pre-season matches. Despite the short lead-in, Lynch would be selected to make his Richmond debut in round 1's season-opening match against Carlton, where he kicked three goals including the first of the season. He followed that performance with another three goals in round 2, but with the loss of fellow tall-forward Jack Riewoldt to injury in that match, Lynch assumed responsibilities as the club's primary forward target in round 3. He kicked four goals in that match before adding six more in round 4's win over Port Adelaide, taking second place in the race for the Coleman Medal. Lynch's 16 goals in the first four rounds of the season marked the most by a Richmond player since Matthew Richardson kicked 20 goals to open the 1994 season. He faced a considerable drop in form over the next month however, going goalless on two occasions and scoring just one goal total in the three game period to round 7. During that period Lynch was labelled a "liability" by 3AW commentator Matthew Lloyd for his poor mobility and failure to impact games defensively. Richmond coach Damien Hardwick rebuked those comments however, claiming Lynch was performing well given his injury status and suggesting a return to his best form was yet to come. Lynch himself responded in turn, recording 15 disposals along with two goals and a match high six contested marks in round 8's win over Fremantle. After three goals in round 9, Lynch ranked third in the competition for marks inside 50, sixth for contested marks and had kicked the third most goals of any player in the league that season. In round 10 he suffered a corked calf, sitting out the final quarter of that match but not missing a further match as a result of the injury. In early June Lynch drew criticism from Seven Network commentator Wayne Carey for his continued struggles at impacting the game outside his goalscoring, with Carey highlighting poor disposal, mark and score involvement averages despite Lynch being a target of 30 per cent of Richmond forward-50 entries that season. Despite the criticism, Lynch remained highly ranked among league players for goals (fifth), contested marks (third) and marks inside-50 (fourth) at the time of Richmond's mid-season bye. Lynch begun a full load of mid-week training sessions for the first time at Richmond following the bye, and showed an immediate uplift in scoring with three goals in each of his next two matches. He was also co-best on ground with nine coaches votes in the last of those, an away win over his former side Gold Coast. Lynch retained the number one forward title even after fellow key forward Jack Riewoldt made a return from injury in round 17, kicking three goals in that match before adding three and five in rounds 18 and 19, respectively. He earned selection to AFL Media's Team of the Week in those two matches and earned 15 coaches votes total, including eight as co-best-on-ground in round 18. Lynch played his 150th career match in round 20's win over Melbourne, kicking one goal in that match before adding a total of six more over the final three matches of the home and away season. Lynch finished the regular season with the second most contested marks (47) and second most marks inside 50 (66) of any player in the league that year. Though he missed out on a spot in the All Australian team and even the squad of 40 players, Lynch was named by AFL Media as a notable exception from the squad that year. In September, Lynch played in his first AFL final, kicking two goals and taking six marks as his side defeated the higher seeded Brisbane Lions by 47 points in qualifying final at The Gabba. He was a standout best on ground in a preliminary final victory over Geelong a fortnight later, kicking a match-high five goals along with 10 marks and 19 disposals. Lynch became a premiership player the following week when his side defeated Greater Western Sydney by 89 points in the grand final. He collected seven marks and 13 disposals while kicking two goals in the match. At the end of the season and finals series he was named as the league's third best forward and 18th best player overall in the Herald Sun chief football reporter Mark Robinson's list of the league's best players in 2019. He ranked third (63) in the competition for total goals across the season and finals as well as first in both contested marks (56) and marks inside 50 (77). Lynch finished the season as Richmond's leading goalkicker and became just the third Richmond player in the past 25 years to kick 50 goals or more in a season. He also earned the Kevin Bartlett Medal as fifth placed in the club's best and fairest count that year.