[11] He arrived at Saturday Night Live the same week as Bill Murray with whom he ended up sharing an office overlooking 50th Street, but he mostly began writing at SNL with Al Franken, Tom Davis, and Dan Aykroyd.
By the 1979–1980 season, Lorne Michaels had lost both Dan Aykroyd and John Belushi to feature film careers, causing him to look to writers like Downey, Tom Schiller, Dan Aykroyd's brother Peter, Al Franken, Alan Zweibel, and Tom Davis to fill spots as cast members (along with SNL bandleader Paul Shaffer and newcomer Harry Shearer).
After leaving SNL, Downey became head writer of Late Night with David Letterman for a little over a year, 1982 to 1983, during its formative stages.
[14] Former SNL Weekend Update anchor Dennis Miller has called him the second most important person in the history of Saturday Night Live, behind only creator Lorne Michaels.
[16] Although he was only a credited actor on Saturday Night Live for one season, Downey appeared in over 40 sketches from 1977 to 2005, his most notable being parody commercials such as Craig's Travellers Checks, First CityWide Change Bank, and Grayson Moorhead Securities.
His brief role in that film included a famous monologue in which he insults the title character, played by Adam Sandler, concluding with the sentence "I award you no points, and may God have mercy on your soul."
Downey also had a bit part in Paul Thomas Anderson's 2007 film There Will Be Blood, where he plays Al Rose, Little Boston's real estate broker.
[21] In the Huffington Post, former SNL head writer Adam McKay called Downey "right-wing" and an "Ann Coulter pal".
"[23] In early 2008, Downey wrote sketches for SNL mocking the then-ongoing Democratic presidential debates that depicted the news media as biased toward Obama.
[22] In response, Downey "said he probably favored Mr. Obama over Mrs. Clinton, but that he genuinely felt she was receiving tougher treatment from the news media".