Steve Young has the best career passer rating for the 49ers, with a 101.4 rating.

all-time 49ers passer rating leader
Interpreted as:
all-time 49ers passer rating with a minimum of 750 passing attempts leader
YoungGaroppoloMontanaKaepernickGarciaSmithBrodieTittleDeBergSpurrier101.498.193.588.988.379.172.370.063.161.2
NAMEGPRATEATTCMPPCTYDSAVGYDS/GTDTD%INTINT%SCKSCKY
Steve YoungSteve Young150101.43,6482,40065.829,9078.2199.42216.1862.42901,571
Jimmy GaroppoloJimmy Garoppolo3198.188359667.57,3528.3237.2465.2262.968468
Joe MontanaJoe Montana16793.54,6002,92963.735,1247.6210.32445.31232.72821,902
Colin KaepernickColin Kaepernick6988.91,6921,01159.812,2717.3177.8724.3301.81711,060
Jeff GarciaJeff Garcia7488.32,3601,44961.416,4087.0221.71134.8562.4103570
Alex SmithAlex Smith8079.12,1771,29059.314,2806.6178.5813.7632.91961,182
John BrodieJohn Brodie20172.34,4912,46955.031,5487.0157.02144.82245.047380
Y.A. TittleY.A. Tittle11270.02,1941,22655.916,0167.3143.01084.91346.1
Steve DeBergSteve DeBerg3963.11,20167055.87,2206.0185.1373.1605.048389
Steve SpurrierSteve Spurrier9261.284044152.55,2506.357.1333.9485.750367
StatMuse has season-level data for passer rating and passing attempts going back to the 1932 season.

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