However, ABC executives were impressed enough with her to enroll her in the company's "talent development" program, which paid its participants until they could find appropriate roles.

Dawber's professional breakthrough came when Marshall chose her, despite her having relatively little acting experience and not having auditioned for the part, as one of the two title characters of the ABC sitcom Mork & Mindy, which ran from 1978 to 1982.

She portrayed Mindy McConnell, the comedic foil and eventual love interest for the extraterrestrial Mork from the planet Ork, played by a then-unknown Robin Williams.

[5] The only major difficulty for her on set was that she often found it impossible to maintain the proper composure in character in the face of her co-star's comedic talent.

Also, pressure came from the ABC network to sexualize her character as the series progressed, which Dawber successfully resisted, with Williams's support.

From 1986 to 1988, Dawber again had a title role in a television series, playing Samantha Russell in the CBS sitcom My Sister Sam, co-starring Rebecca Schaeffer.

For the first time in her career, she appeared with her husband, fellow actor Mark Harmon, on CBS's NCIS in 2021 for seven episodes as '"seasoned investigative journalist" Marcie Warren.