Newcastle's campaign ended in a narrow 19-18 defeat, but the Knights earned respect after a demanding preliminary-final victory the previous weekend.
The Roosters' grand final win also provided a fitting send-off for Daly Cherry-Evans, bound for Super League, and Mark Nawaqaanitawase, who is moving to rugby union.
James Tedesco claimed his first Clive Churchill Medal, while Spencer Leniu played a decisive part in the victory.
Leniu's Roosters tenure has been turbulent, with criticism following a racism scandal that shook the NRL.
His $850,000 salary attracted scrutiny, and he fell out of favour with coach Trent Robinson at various points.
But Leniu delivered when it mattered, after an important conversation with Robinson the day before the final.
After the match, Robinson praised the prop, who had left Penrith as a premier and could now depart the Roosters with another title.
The 19-18 result brought the 2026 season to a close.