After Sen. Chris Dodd announced on January 6, 2010 that he would retire at the end of his term, Richard Blumenthal told the Associated Press that he would run in the election for Dodd's seat in November 2010.[83] Later that day, President Barack Obama and Vice President Joe Biden called Blumenthal to express their best wishes.[84]

The same day, Public Policy Polling released a poll they took on the two preceding evenings, including races where Blumenthal was paired against each of the three most mentioned Republicans contending for their party's nomination for the seat. He led by at least 30% in each hypothetical race: against Rob Simmons 59–28, against Linda McMahon 60–28, and against Peter Schiff 63–23, with a ±4.3% margin of error cited.[85] Rasmussen Reports also polled after Blumenthal announced his candidacy and found a somewhat more competitive race, but with Blumenthal holding a strong lead.

A February poll by Rasmussen found that Blumenthal held leads of 19 (against Simmons) and 20 (against McMahon), and that Republicans had made up little ground since the initial Rasmussen poll after Blumenthal announced.[86] On May 21, Blumenthal received the Democratic nomination by acclamation for Senator of Connecticut, after opposing candidate Alpert was not allowed to speak at the convention by the committee, except to withdraw his name for nomination after preparing a speech.[87][88]

Days after the nomination, Quinnipiac University polling indicated that Blumenthal held a 25-point lead over McMahon.[89] The Cook Political Report changed its prediction on the race to Leans Democratic, making Blumenthal the favored candidate over McMahon.[90]

On the November 2nd election, Blumenthal was elected into the U.S. senate, defeating former WWE CEO Linda McMahon, 55% to 43%.