It was a long road to such stardom. O'Connor had studied in Ireland and performed on stage in Dublin and other parts of Europe, before returning to the U.S. in the early 1950s. Work was scarce, but beginning in the early 60s, he began winning supporting parts in feature films and guest appearances on TV series. In 1961 alone, O'Connor could be seen in "By Love Possessed", "A Fever in the Blood" and "Parrish" on the big screen, and a year later he was in "Alcoa Premiere" and "The Dick Powell Show" on the small screen. Although he made his first TV pilot in 1963 with "Luxury Liner" for NBC, and appeared in "Cleopatra" that same year, possibly O'Connor's best-known role in the 60s was Charles Bromley in "Hawaii" (1966), the Massachusetts church elder organizing the missionaries. Hollywood writer-producer Norman Lear was aware of O'Connor and his work and in the late 60s cast him as Archie Bunker in two pilots for ABC based on the British series "'Til Death Do Us Part". The network balked at giving the potentially controversial series a weekly berth, but CBS picked it up. Instant TV stardom followed, including talk show appearances and specials. But O'Connor was most interested in the work. He battled frequently with the writers about what Bunker would say and would do. Lear publicly supported O'Connor's creativity, giving O'Connor the lion's share of the success of the show. (O'Connor also wrote the closing theme.) Using his clout at CBS, O'Connor created and co-executive produced "Bronk", a one-season series starring Jack Palance. He also produced a number of other TV projects, and was earning the then unprecedented $100,000 per episode salary for portraying Bunker. In 1979, Rob Reiner and Sally Struthers departed "All in the Family," and O'Connor and Jean Stapleton, who had won celebrity of her own as Edith Bunker, moved on to a sequel, "Archie Bunker's Place". Archie, now half the bigot he used to be, owned a bar-restaurant (with a Jewish partner, no less) and the couple was also raising Edith's little girl cousin. Stapleton departed the series a year later with an emotional episode in which Edith had died in her sleep and Archie and Stephanie, his ward, are left to mourn. O'Connor battled CBS executives often during the run of "Archie Bunker's Place", on which he had almost complete creative control. The series was canceled in 1983 and O'Connor swore he would never work for CBS again. He took off for New York to make his long-delayed Broadway debut in "Brothers".
Returning to Hollywood, O'Connor wrote and directed episodes of "The Redd Foxx Show" (ABC, 1986) and made sporadic dramatic appearances in TV-movies. O'Connor, again with autonomy, returned to series TV as Chief Bill Gillespie in a show based on the feature film "In the Heat of the Night" (NBC, 1988-92; CBS 1992-94). Filmed in Georgia, the show followed Gillespie as he dealt with the activities in a small Southern town, and traced his growth from a bigoted individual to one who accepts diversity without card-carrying for any political agenda. NBC canceled the series after two seasons, and when CBS picked up the show, O'Connor found himself back at his old network. The new marriage worked. Not only did the series last as a weekly effort, but Gillespie married an African American woman, (portrayed by Denise Nicholas), a feat that would have seemed inconceivable for TV over twenty years earlier when Archie Bunker made his appearance. Following its cancellation, "In the Heat of the Night" returned to CBS as a series of TV-movies. O'Connor was now firmly positioned as a TV icon. He was among the first batch of notables awarded a bust at the Academy of Television Arts & Sciences Building in North Hollywood, and was elected to that group's Hall of Fame in 1990.
Tragedy struck in March 1995 when O'Connor's only child, an adopted son Hugh, a part-time actor who had been battling drug addiction for some time, committed suicide. Battling tears, O'Connor appeared before TV cameras to indict drugs as the culprit. He blamed the man who sold the drugs to his son and fought to see him brought to justice. The dealer was convicted in January 1996. After months out of the public eye, the still paunchy, still white-haired, now older O'Connor joined the cast of the Fox TV series "Party of Five" in the recurring role of the orphans' grandfather. His last film appearance was a the co-owner of an Irish-Italian restaurant in "Return to Me" (2000).