Keep your mouth shut. And we got no problems.
We're always doing stupid things.
Frank Delfino is one of the main characters of How to Get Away with Murder. He is a local Philly boy who never thought he'd be the type of guy who wears a suit to work. But he also never thought he'd get to work for someone like Annalise Keating. Forever loyal and armed with hometown connections, Frank is ready to do Annalise's dirty work at every turn. His street-smart, tough-guy exterior makes him the ideal protector for Annalise. His number one vice though? Sleeping with the students.
"Unlike any other teacher you have ever had, I do believe there are stupid questions." ("Pilot")
Annalise Keating introduces Frank as her paralegal whom the students can go to for help. Frank makes it clear that unlike any other teacher those students have ever had, he does believe there are stupid questions, so if they have any then to address them with Bonnie. He is also there, with Bonnie, when the class present their ideas. That evening, when Wes comes up with an idea to present to Annalise, he enters her office, walking in on her getting ready to have sex with Nate Lahey. The annoyed professor calls Frank, telling him that he didn't lock the doors again. Frank and Bonnie are present when Annalise presents new information, obtained by Connor, to the court. Later on, Laurel goes to Frank about realizing Gina is friends with Agnes Kaufman, only to find out he already knew, and is representing a guilty client this whole time. After Laurel leaves, furious, Bonnie, having witnessed this whole encounter, tells Frank to stop "screwing the students." The following day, after learning Gina bought aspirin the night before the attempted murder, Annalise is upset with Frank for not getting that bit of information out of the client. They end up winning the trial, however, after Nate is brought in to testify. Frank is then present when Annalise reveals who will come to work at her firm and Bonnie gives Frank suspicious looks when its revealed Laurel is one of them. ("Pilot")
Frank comes a-callin'. ("Pilot")
After the murder of Sam Keating, the four law students, Laurel, Wes, Michaela, and Connor flee to the woods near the university in a panic and to decide their next plan of action. Wes brings with him the murder weapon, a golden statue, and they decide to return it after cleaning it. The group then argue over whether or not they should dispose of the body. However, a coin toss determines that they bury it. When they go to collect the body, they wrap it up in a carpet and carry it outside, and to the woods and they're almost caught by two drunken teenagers who are there looking for some privacy. Laurel's phone rings, Frank having called her. The others wonder what is going on and why he would call. Once they leave and they're in the clear, they take the body to a secure location and decide for one final time if they want to get rid of the body. Everyone is now in agreement and end up burning the body, disposing of all the DNA. ("Pilot")
In the final episode, Frank is seen killing Lila at the request of Sam.
In Season 2 it is hinted that Frank is some kind of hitman or bodyguard. Since it is clear he is more than just a paralegal, the Keating 5 suspect that he has a nastier job, but they don't have the time to dwell on it. A series of flashbacks show him involved in suspicious activity - murdering Lila, asking Annalise if he wants her to take care of Hannah Keating for her, and planting Nate's fingerprint on Sam's wedding ring. He's also shown to have many suspicious connections, and after Rebecca is killed, he is the one who disposes of her body. In "Meet Bonnie," he hides meth in Levi's car and frames him for possession of drugs.
Frank admits to Laurel that he killed Lila, then she leaves him.
It is later revealed that Frank was responsible for the car crash that killed Annalise's baby, which is why he had to kill Lila for Sam, because he held this over him.
Frank runs away and takes the suitcase full of cash with him (which he most likely never spent due to his guilt) at the end of the Season 2 finale.
This is a gallery of photographic stills released to promote the character.