In 1950, Pettersen became one of the first women in New Jersey to be licensed as an architect. She began her career as a
draftsman for, and later an apprentice to,
Frank Lloyd Wright, working in Arizona and Wisconsin at
Taliesin; She lived in Tennessee from 1946 to 1950, during which time she designed power buildings and facilities for the
Tennessee Valley Authority. During those 50 years, she designed more than 600 projects, both residential and commercial. Pettersen was primarily a residential architect. She became the first female president of the
American Institute of Architects' (AIA) New Jersey chapter in 1985 and its first female regional director two years later. She was appointed to the AIA College of Fellows in 1991. In 1965, she was the first female recipient of
Cooper Union's Professional Achievement Citation for Distinguished Accomplishments. She was the first woman appointed by the governor to the New Jersey State Board of Architects and subsequently its first woman president (1975–1976). In 1984, she became first female president of the New Jersey Society of Architects. From 1968 to 1970, Pettersen served as president of the
Bergen County Altrusa Club, which is an organization for professional women. ==Awards and exhibitions==