Mike Lookinland's father was a Vice Principal at San Pedro High School, located in San Pedro, California, part of the Los Angeles Unified School District (LAUSD), in the late 1970s. He has a younger brother named Todd. Lookinland grew up as a Mormon. He is a self-professed conservationist and "camping nut". He attended the private Chadwick School on the Palos Verdes Peninsula in Southern California, and graduated in 1978.

Lookinland was a TV commercial actor before he was cast in The Brady Bunch, having done around thirty commercials. He has naturally sandy-colored wavy hair. Because his hair color did not match Peter's or Greg's natural dark brown color, he had to have his hair dyed dark brown and straightened to match. Occasionally, the lights on set though were so hot that his dye job would sometimes run down his face. During the last two seasons of The Brady Bunch, his natural hair color was finally allowed to show. Bobby (Mike) was always the type of kid who was sweet, funny, energetic, and sometimes dramatic during his role on the Brady Bunch.

Lookinland's brother, Todd, appeared in a Brady Bunch episode that served as the pilot for a spinoff series about a husband and wife that adopt three boys, one white, one black, and one Asian. The pilot was not bought, however. In another episode during the show's final season, Bobby kisses a girl named Milicent (Melissa Sue Anderson) and he sees “sky rockets.” She then informs him that she may have the mumps and he "shouldn't have done that." Bobby and his family nervously await her telephone call with the doctor's results. Years later, the two reunited on an episode Little House on the Prairie, on which Anderson played Mary Ingalls, and Lookinland guest starred.

Lookinland also provided the voice of Oblio in the animated film The Point!. Shortly after the final season of The Brady Bunch wrapped filming, he appeared alongside Jennifer Jones and Paul Newman in the 1974 disaster film The Towering Inferno and on the 1970s TV show The Secrets of Isis.

Lookinland reprised his role as Bobby Brady in the 1988 Christmas special A Very Brady Christmas, and again in the 1990 sequel series The Bradys, in which Bobby Brady was involved in a racing car accident, which confined him to a wheelchair throughout the series.

Since 1987, Lookinland has been married to Kelly Wermuth. Kelly worked as a script supervisor on Touched By An Angel. They have two sons: Scott (born 1990) and Joe (born 1993). He was portrayed by his son Scott in the TV movie Growing Up Brady.