Walsh is portrayed by actor Jack Falahee, who auditioned for the role on How to Get Away with Murder during the television pilot season (January to February) in 2014.

[2] By February, Falahee joined the series' creator and executive producer, Peter Nowalk, for screen tests in the role of Walsh;[2] the scene was for the pilot episode, whereby the character is at a bar trying to pick up Oliver.

[3] Nowalk was full of awe in response to Falahee's audition, adamant that, "[f]rom the minute he opened his mouth, he sounded just like Connor should".

[4] When being tested for HIV in "It's All My Fault", the clinic nurse asks him how many sexual partners he had during the past year, to which he estimates between 30 and 40.

[6] In the pilot episode, Walsh is introduced as a law student of Middleton University, a college in Philadelphia.

He meets Oliver at a bar, a computer technician, who he sleeps with in order to obtain the information he needs to gain the admiration of Professor Keating.

[7] In "Let's Get to Scooping", Walsh has sex with Paxton Curtis, someone he suspects is behind insider trading at the brokerage firm of Keating's client, Marren Trudeau (Elizabeth Perkins).

Curtis commits suicide, to which Walsh is left visibly distraught and feeling survivor's guilt.

[8] In "Smile, or Go to Jail", Walsh reveals that he attended boarding school with Michaela Pratt's fiancé Aiden Walker (Elliot Knight); he discloses to Pratt that Walker may be gay, as the two previously shared a relationship while at school.

[10] Walsh and computer technician Oliver Hampton (Conrad Ricamora) have had an on-and-off relationship almost from the inception of the series.

In the pilot episode, the two meet at a bar, wherein Walsh seduces Hampton into giving him illegal documents to bolster a case of Keating's.

[7] Throughout the first few episodes of the series, the two continue to have a casual sexual relationship while Hampton assists Walsh in obtaining information.

[8] Months later, Walsh shows up unannounced to Hampton's place, after burning Sam Keating's body, freaking out and telling him that he "screwed up".

[10] In the penultimate episode of the first season, "The Night Lila Died", the two agree to get tested for sexually transmitted diseases (STDs).

[15] Even though Connor disapproves, in "Two Birds, One Millstone", Oliver helps Annalise and Keating 5 in the Caleb-Catherine Hapstall case by hacking and finding a prospect suspect lead, Phillip Jessup.

Connor goes back to his usual sex escapades with guys from "Humpr" and doesn't make an effort to hide it.

At a party sponsored by Annalise after the entire class cleared their midterms, Connor gets drunk and Oliver worries about him, reminding him about his drug problem.

Connor, in his drunken state, confesses that he lied about being an addict and that he wasn't high that night (when Sam was murdered) but was traumatized.

Oliver, now aware of all the murders, tries to be understanding of how Connor handled everything alone while he can't bring himself to go by his usual way.

As he is arrested following Annalise's exoneration, Connor hands his wedding ring over to Oliver, who refuses to accept the divorce.

In the flash-forwards in the series finale, its shown that Connor and Oliver's relationship ultimately did survive and they didn't get divorced.

Connor and Oliver are seen attending Annalise's funeral together years later, waving at Laurel, who identifies them as old friends to her now-adult son Christopher Castillo.

After learning about Connor applying for Stanford, Michaela asks him to stay back saying "I can't survive here without you".

In "We're Bad People", Connor revealed to Wes that he was going to therapy nowadays like he did when he was 17 and was struggling with coming-out issues, and jokes that except this time he talks about the murders.

After Wes died, Connor did not have kind words for him, which was him channeling his grief in a bad way, which lead Asher and Laurel to dislike and suspect him.

In "He Made a Terrible Mistake", after learning about Connor's role on the night Wes was murdered, Laurel goes on a rant against him saying he's lying, he's the reason Wes died, and that, he should take a gun and kill himself, unaware that Connor is already struggling with suicidal thoughts.

After the first season of Murder (2014–15), Connor Walsh was ranked by IndieWire thirteenth in a list of "best LGBT characters on television".

[19] TVOvermind praised Falahee for his portrayal of Walsh, contending that the actor "plays his role to a tee.