For much of the election cycle following the primary election, political analysts theorized early on that the strength of Cooley's name after being twice elected District Attorney in Democratic-leaning Los Angeles County, being viewed as a rising star in the California Republican Party along with the strength of Meg Whitman's well-funded campaign anchoring the California Republican ticket in 2010 made Steve Cooley the initial favorite by a slight margin to win the election.
Kamala Harris coalesced Democratic support with her opposition to Proposition 8, which Cooley promised to defend in court, opposing the unpopular Proposition 23 and any proposal for an SB 1070-style law in California. Harris benefitted from an endorsement and joint appearance with President Barack Obama at a rally at the University of Southern California before election day as well as a focus of the Los Angeles County Democratic Party on promoting her candidacy in Los Angeles County towards the final weeks of the campaign, which promised to make the race competitive.
On election night, the headliners on the Republican ticket, Meg Whitman and Carly Fiorina were soundly defeated by Jerry Brown and Barbara Boxer, with Democrats having a healthy margin to declare victory in every other statewide contest, save for attorney general. Abel Maldonado, who was defeated for his reelection bid as Lieutenant Governor, stated that errors of the Whitman and Fiorina campaigns dragged Republican candidates on the bottom of the ticket down along with the fading fortunes of Whitman and Fiorina towards the end of the race. 
The only bright spot statewide for the California Republican Party that night were early returns showing Cooley with a lead of up to eight points, in which he and many news organizations declared victory. However, the next morning, returns from Los Angeles County, which was believed to be a Cooley stronghold came in strong for Kamala Harris, removing one of Cooley's key advantages and making the race too close to call. Cooley then canceled a victory press conference scheduled for that day.
Los Angeles and San Francisco County reported their returns, which favored Harris with less than 38,000 votes (45.9% versus 45.7%)  separating both candidates at the end of counting that day.
On November 24, 2010, Cooley conceded the race when it was determined that he was going to be unable to overcome the 50,000-vote lead that Harris had built up and maintained during the past week, with a majority of the uncounted ballots coming from counties which Harris won. The closest statewide race of the 2010 cycle in California, Cooley is the top vote-getter of the 2010 Republican ticket, while Harris's victory gave the Democratic Party a clean sweep of all of California's statewide offices - a feat the party last accomplished in 2002.
The following were certified by the California Secretary of State as candidates in the primary election for Attorney General. Candidates who won their respective primaries and qualified for the general election are shown in bold.