She received both popular and critical acclaim, most notably for her femme fatale roles in film noir with Alan Ladd during the 1940s, and was well-known for her peek-a-boo hairstyle. Her success did not last; she had a string of broken marriages and long struggles with mental illness and alcoholism until she died of hepatitis.
Her breakthrough film was I Wanted Wings in 1941, a major hit in which Lake played the second female lead and was said to have stolen scene after scene from the rest of the cast. This success was followed by Hold Back the Dawn later that year. She had starring roles in more popular movies, including Sullivan’s Travels, This Gun for Hire, I Married a Witch, The Glass Key, and So Proudly We Hail!. Looking back at her career years later, Lake remarked, “I never did cheesecake; I just used my hair.”
For a short time during the early 1940s Lake was considered one of the most reliable box office draws in Hollywood. She became known for onscreen pairings with actor Alan Ladd. At first, the couple was teamed together merely out of physical necessity: Ladd was just 5 feet 5 inches (1.65 m) tall and the only actress then on the Paramount lot short enough to pair with him was Lake, who stood just 4 feet 11½ inches (1.51 m). They made four films together.
A stray lock of her shoulder-length blonde hair during a publicity photo shoot led to her iconic “peekaboo” hairstyle, which was widely imitated. During World War II, she changed her trademark image to encourage women working in war industry factories to adopt more practical, safer hairstyles.
Although popular with the public, Lake had a complex personality and acquired a reputation for being difficult to work with. Eddie Bracken, her co-star in Star Spangled Rhythm was quoted as saying, “She was known as ‘The Bitch’ and she deserved the title.” In that movie, Lake took part in a song lampooning her hair style, “A Sweater, A Sarong and a Peekaboo Bang”, performed with Paulette Goddard and Dorothy Lamour. Joel McCrea, her co-star in Sullivan’s Travels, reputedly turned down the co-starring role in I Married a Witch, saying, “Life’s too short for two films with Veronica Lake.” 
Lake’s career stumbled with her unsympathetic role as Nazi spy Dora Bruckman in 1944’s The Hour Before the Dawn. During filming, she tripped on a lighting cable while pregnant and began hemorrhaging. She recovered, but her second child, William, was born prematurely on July 8, 1943, dying a week later from uremic poisoning. By the end of 1943 her first marriage ended in divorce. Meanwhile, scathing reviews of The Hour Before Dawn included criticism of her unconvincing German accent.
Nonetheless, Lake was earning $4,500 per week under her contract with Paramount. She had begun drinking more heavily during this period and people began refusing to work with her. Paramount cast Lake in a string of mostly forgotten films. A notable exception was The Blue Dahlia (1946), in which she again co-starred with Ladd. During filming, screenplay writer Raymond Chandler referred to her as “Moronica Lake”. Paramount decided not to renew her contract in 1948.
She married film director Andre De Toth in 1944 and had a son, Andre Anthony Michael De Toth, known as Michael De Toth (October 25, 1945 – February 24, 1991), and a daughter, Diana De Toth (born October 16, 1948). Lake was sued by her mother for support payments in 1948.
Lake earned her pilot’s license in 1946 and was able to fly solo between Los Angeles and New York.