In a recent episode of the superb TNT series “Saving Grace,” the character Father Johnny Hanadarko (played by Steppenwolf Theatre’s Tom Irwin), the brother of anti-heroine Grace Hanadarko (Oscar-winner Holly Hunter), makes a revealing confession about his faith:

“When I was a kid, I tried to figure out how God could be everywhere at once. I’d think of the most unlikely places — in my father’s Scotch, in my sister’s bra. God was this fun, fun mystery. I think I’ve lost that. These days, I spend my time worried if the air conditioner is going to work on Sunday so that Mrs. Bernardi doesn’t hunt me down for the 89th time.”

I am a longtime and rabid fan of “Saving Grace,” which concludes its third season at 9 p.m. Tuesday, and much about the series’ edgy exploration of faith, doubt, God, religion and relationships often gives me spiritual meat to gnaw on.

Father Johnny’s monologue was a full meal.

How true? When you grow up with religion and faith, as Father Johnny has, sometimes the mysteries of God lose their, well, mystery. The wonder leaves the room, replaced by intellectualism and the temporal distractions of adult life.

Rather than some kind of indictment of Catholicism, the priesthood or organized religion in general, Father Johnny’s admission was a clarion call to seek the mystery, the face of God; to enliven faith by living it.

On the eve of this season’s finale — fans will have to wait until next summer for the fourth season — I had a chat with “Saving Grace” creator Nancy Miller, herself a woman of deep and complex faith, a self-proclaimed “practicing Catholic” whom her publicist describes (quite accurately) as “a gutsy, take-no prisoners broad.”

In three seasons, Grace, a rowdy Oklahoma City homicide detective, has slogged through her own childhood abuse at the hands of a pedophile priest, alcohol abuse, torrid (and often graphically depicted) love affairs and all manner of life- (and faith-) shaking chaos and destruction.

Still, Grace’s biggest struggle has been with God, or, more precisely, with a last-chance angel named Earl (Leon Rippy) sent by God to help Grace — and those she loves — find healing. Grace and Earl wrestle weekly over God’s will for both of them.

Faith can be terribly complicated, and it is a topic that Miller handles with equal parts tenderness and humor.

“I had a great conversation with a friend of mine who is a priest, about difficult people in the parish and how he deals with them and how hard it is for him,” Miller said. “A priest has to be a social worker, a psychiatrist, a theologian — they’re like cops, they wear so many different hats. And I think Johnny has forgotten the fun of God, forgotten the joy, the childlike joy of this wonder that God has placed before us, not only in other people but in a tree, in coffee grounds on the floor. If he would only look at things differently, he might see something different.

“So that’s sort of how we’re thinking of Johnny these days, and he has dedicated his life to God, and yet his messed-up sister gets the angel? It’s got to be so confusing to him.”

This season, Miller introduced a new character named Neely, a young African-American woman addicted to methamphetamines to whom Earl also has been assigned as a last-chance angel. After meeting her first in a dream and then at a crime scene (where Neely is shot in the head and winds up in a coma), Grace has spent much of this season trying to find out who Neely is and what she means to her life.

“Grace kept going, kept taking steps, back to Neely, which is huge. . . . She’s going toward this girl, with no explanation of why, but she keeps doing it. And that’s, I think, faith, especially in those times where it’s like: What the hell is going on?”

Even Earl has shown his more human(ish) side this season, questioning God (in the form of a silent dog with an extra-long tongue) and God’s plan for Grace.

“We wanted to make it clear that Earl is not God. He is an angel, and he is the messenger. And there are some messages that God does not give him, so he is in the dark,” Miller said.

When Grace went missing (held captive by a deranged childhood friend who tattoos angels wings on her back) in an episode earlier this season, Earl enlisted the help of an angel army to find Grace when God wouldn’t tell him where she was.

“God didn’t reveal that to him and there’s a reason,” she said. “You’ll find out in next week’s episode … I don’t want to give it away. … You’ll be surprised that the lesson in this episode has to be learned by Earl.”

Tuesday’s season finale — titled “Am I going to die today?” — has me on pins and needles. If you’ve never watched “Saving Grace,” you should. The first three seasons are available on iTunes and Amazon.com.

So what happens next?

“God is a mystery. What He wants sometimes for us is a mystery, and all we have to go on is faith,” Miller said. “If you don’t have faith, you’re gonna get off path, and even with faith, you still might get off path. … Just because you believe in God all your problems aren’t solved, all the pain isn’t taken away, and He never promised us that.

“I like to keep the show messy because I just think we’re messy — life is messy and human beings are just messy.”

“Saving Grace” airs Tuesdays at 9 p.m. on the TNT cable channel.