I report observations on the ecology and trends in growth and relative condition of Salvelinus namaycush (Lake Trout) in Quabbin Reservoir garnered from over 60 y of almost continuous monitoring. Fish were captured using gillnets during the spawn in late October and early November in 10–15 m of water. Spawning began when waters reached 17 °C, but activity was most intense between 11 °C and 13 °C. Spawning fish were 4–24 y old, and catches were typically comprised of 89.5% males. Male Lake Trout generally reached 457 mm (18 in; legal harvest size) by age 5, and since 2010, average growth of mature males was 5.8 mm per year. Length-at-capture and density have declined over the period of record but rose and fell over shorter intervals, likely in response to forage abundance, mainly Osmerus mordax (Rainbow Smelt).