Garson regularly appeared on boxoffice polls of the top ten stars during the WWII years; indeed, Betty Grable was the only female star who surpassed Garson in popularity during this time. Garson formed an attractive romantic partnership with the stalwart and gentlemanly Walter Pidgeon, with whom she co-starred eight times. Their finest pairings came with "Madame Curie" (1943) and "That Forsyte Woman" (1949), though popular memory regularly casts them as Mr. and "Mrs. Miniver" (1942), a then-acclaimed but rather overrated tribute to the stiff-upper-lip spirit of the British in WWII, for which she earned an Oscar. Garson also played quite well opposite popular matinee idols Ronald Colman in the delicate, sentimental romance, "Random Harvest" (1942) and Gregory Peck in the lavish family saga, "The Valley of Decision" (1945).

Garson's popularity began to ebb during the late 40s, the regal and dignified stoicism she embodied for the war years seeming less suitable in the face of postwar angst and malaise. Some of the attempts to vary Garson's image and type of roles, such as in the zany farce "Julia Misbehaves" (1948), were not particularly successful, but she continued on into the middle of the following decade with such smaller-scale vehicles as "Scandal at Scourie" (1953) and "Strange Lady in Town" (1954). She later made a comeback with her acclaimed performance as Eleanor Roosevelt opposite Ralph Bellamy in "Sunrise at Campobello" (1960) and also did periodic stage work. Her last feature acting role was in 1967's "The Happiest Millionaire" and her final film appearance was in the documentary "Directed by William Wyler" (1986). Garson, who had worked sporadically in TV since the 1950s, made one of her last acting appearances as Aunt March in the miniseries "Little Women" (NBC, 1978). After dabbling briefly in theater producing (notably the New York production of "On Golden Pond"), she retired in 1980 after suffering a heart attack. Eight years later, she underwent bypass surgery. Garson succumbed to heart failure at age 92 on April 6, 1996.

The actress was married three times. Her second husband (1943-47) was actor Richard Ney, who had played her son in "Mrs. Miniver".