“Not all songs have a story,” David Foster says. “But these five do.”

He would know: In a career that stretches across more than half a century — and which took him from his native Canada to his longtime home of Los Angeles — Foster has written, produced, arranged, played on, executive-ized or reality-TV-coached the performance of an endless array of songs, among them some of the biggest (and most shamelessly sentimental) in pop history.

Celine Dion’s “Because You Loved Me”? “The Prayer” by Dion and Andrea Bocelli? “Glory of Love” from “The Karate Kid Part II”? All Foster joints, which doesn’t even get to the work he’s done with — deep breath here — Michael Jackson, Barbra Streisand, Chaka Khan, Madonna, Michael Bublé, Kenny Rogers, Josh Groban, Lionel Richie and Mary J. Blige.

On Sunday night at the Hollywood Bowl, Foster will look back at this lifetime of songs in an all-star concert to mark his 75th birthday. The lineup includes Bocelli, Bublé, Groban, Jennifer Hudson, Charlie Puth, Kristin Chenoweth, Brian McKnight, El Debarge and, not least, Foster’s wife, singer and actor Katharine McPhee.

Ahead of the show, Foster got on the phone between tour dates to tell the stories behind five of his signature tunes.

Earth, Wind & Fire, ‘After the Love Has Gone’ (1979)

Co-written by Foster, Jay Graydon and Bill Champlin — and sung with silky finesse by Earth, Wind & Fire mastermind Maurice White — this complicated ballad from the band’s double-platinum “I Am” album earned Foster the first of his 16 Grammy Awards. Foster later released a version by his and Graydon’s short-lived soft-rock band, Airplay.

I was pitching an album to [Motown founder] Berry Gordy, one of my very first productions, and he was lukewarm on it. I said, “But wait — I have more!” But I didn’t have more. He said, “Show me.” So I went to the piano and sat down, and I swear to God, the chorus of “After the Love Has Gone” fell out in real time.

You didn’t have anything when you sat down at the piano.
I had nothing. Totally bulls—ed him.

Tommy Mottola wrote in his memoir that you offered the song to Hall & Oates before Earth, Wind & Fire.
I did offer it to Hall & Oates because I was producing them at the time. But the song didn’t fit with their program — they were trying to go more rock. Then I played it for Maurice White, and I was even more nervous than with Berry Gordy. Maurice, I think, was the greatest. He said, “I’d like to record that song,” which made my heart pound. I said, “When?” He said, “Tonight — and you’re gonna play on it.”

“After the Love Has Gone” peaked at No. 2 on the Hot 100. Remember what blocked it from No. 1?
I sure do: “My Sca-rotum.”

I wondered whether losing to “My Sharona” was particularly vexing.
In retrospect, I love that record too. And I became friends with the drummer [of the Knack]. But yeah, it was a little bit annoying that it was [sings “My Sharona” riff] and we had seemingly so much substance to our song. But, you know, the public doesn’t care about that.

What do you think now of the Airplay version of “After the Love Has Gone”?
It’s a little slick.

Might be a little slow too.
One of the reasons it feels slow is because when we recorded it with Earth, Wind & Fire, we didn’t have a click track. I said, “Maurice, we gotta do it again — we’re playing twice as fast at the end as we are at the beginning.” Listen to it — you’ll hear it. He said, “I don’t care — feels good to me.”

He was right.
He was always right.

Chicago, ‘Hard to Say I’m Sorry’ (1982)

Chicago had long since made its name as a swinging jazz-rock outfit when Foster came onboard for a creative and commercial reboot led by him and the band’s singer, Peter Cetera.

We had finished “Chicago 16,” and Irving Azoff got ahold of us and said, “We have this movie called ‘Summer Lovers,’ and we’d like you guys to write a song for it.’” So Peter came over to my house in Toluca Lake and we banged that sucker out in about an hour. It always helps when you have a movie as a co-writer.

You’re saying you had a theme or an emotion to go off.
We had a scene, actually. In the movie, the song starts — Peter’s going, “Everybody needs…” — and there’s this moped in the distance that Peter Gallagher’s riding, and that f—ing moped gets louder and louder, to the point where it’s obliterating our song.

What do you like about Cetera’s voice?
He’s like a horn section — he would sing so hard and so beautiful and so high. How could you not be inspired listening to somebody doing hum-alongs with you at the piano with that voice? He’d make up fake s—, just syllables and vowels, like songwriters do. But it all sounded perfect to me.

Do you see a parallel between Chicago and the Doobie Brothers or Fleetwood Mac — one of these bands where there’s like a regime change at some point that pretty significantly alters the band’s sound?
I’ve never thought about that, and it didn’t feel that way at the time. But the group was really unhappy back then and to some extent are now. And I get it — I get why they were unhappy. I just came in like a young, arrogant barnstormer: “OK, I’m playing all the piano now.” And Peter let me play the synth-bass on everything because he didn’t want to play bass anymore.

So I was the bass player, I was the piano player, I was the co-songwriter, I was the producer, I was the arranger for the most part. I didn’t know then that I was making them be more like me than I was trying to be like them. I was trying to imitate them, but I guess more of me came out than should have. And they got annoyed because they didn’t want to be a ballad band.

Sounds like a regime change.
I mean, my mission with Chicago was I wanted to remind them of their greatness. I was such a fan in the late ’60s when it was the Transit Authority. But by “Chicago 16” they’d just forgotten their greatness, that’s all. Bottom line is: I don’t blame them for being pissed off.

“Hard to Say I’m Sorry” went to No. 1. Did that success make them less salty?
No, because they’d had a ton of success before. They were so revered — they were critic’s darlings, for the most part. I f—ed that up.

David Foster, ‘Love Theme From “St. Elmo’s Fire” ’ (1985)

Foster’s theme from the Brat Pack classic was the rare instrumental track to crash the pop Top 20 in the 1980s.

I don’t look at a sunset or the ocean and go, “Oh, I can write a song around that.” That’s just not who I am. One of the only times I’ve ever been inspired to write a melody was going across the Lions Gate Bridge in Vancouver — a melody came to me for the love theme of “St. Elmo’s Fire.” I sang it into a tape recorder that I had in the car, and I did a demo and sent it to the director, Joel Schumacher, who I loved working with. He said, “No, no, no, no, no, no — this is totally wrong for my movie.” Obviously, I was crushed and disappointed.

Couple days later, Quincy Jones called me and he said, “We’re doing this thing down here called ‘We Are the World.’ You should do the same thing in Canada.” So I thought about it, and I called Bruce Allen, the manager, and Bruce eventually said yes and we got all the artists together for a Canadian version of “We Are the World,” which was called “Tears Are Not Enough.” And the song that we used — Bryan Adams finished it with his partner, Jim Vallance — it was the song that Joel rejected.

The funny thing is that after Bryan did this amazing demo, Joel calls and he goes, “Oh my God, David, I’ve made such a big mistake — I put your melody up against the movie, and it’s perfect.” I said, politely, “You snooze, you lose.” Then I panicked and ran to the piano and came up with what became “Love Theme from ‘St. Elmo’s Fire.’ ”

Natalie Cole with Nat ‘King’ Cole, ‘Unforgettable’ (1991)

For the title track of her 1991 standards collection, Natalie Cole selected the swank romantic ditty popularized four decades earlier by her father — then cut it as a virtual duet with Nat “King” Cole, who’d died in 1965. The single and the LP went on to win album, record and song of the year at the Grammys.

I was kind of at a low point in my career after the monster ’80s. So when that project came along, I thought, well, I love this kind of music, and I love Natalie. It won’t sell anything, but at least it’ll be a really gratifying musical experience.

She gathered three producers — me, Tommy LiPuma and her husband at the time, Andre Fischer — and we all met at Du-par’s in the Valley. Natalie put 22 song titles out on the table and told us to pick the songs we loved. I picked “Mona Lisa” as my first pick, and then second or third round, I took “Unforgettable.”

Later, Natalie told me, “You picked the song that I want to try and do as a duet with my father. Do you have any idea how you could make that work?” I said, “No, but I’ll figure it out.” And I figured it out: I had Natalie sing, and I had them sing together, and I had Natalie answer her dad. The real hard thing to do was to get him to answer her back. So she goes, “Unforgettable,” and he goes, “Unforgettable,” right behind her. It was like he was over her shoulder.

Now, that would be so easy to do: Move his vocal here, move his vocal there — push of a button. Back then, you can imagine the technology. It was brutal.

The Grammys sweep inspired some backlash from folks who objected to the celebration of this old-fashioned music in the year of Nirvana’s “Nevermind” and Ice Cube’s “Death Certificate.” What’d you make of that?
Nobody said that to my face. Obviously, some were saying it behind my back. I’m sure Nirvana was pissed off, but I’ve been pissed off at the Grammys too.

Whitney Houston, ‘I Will Always Love You’ (1992)

Foster took his second record of the year Grammy in three years with Houston’s iconic rendition of Dolly Parton’s tender country ballad. The song drove sales of the soundtrack of “The Bodyguard” to more than 18 million copies in the United States alone.

Did Whitney know Dolly’s song before she remade it?
She did not. I didn’t know it either.

The story goes that using the song was Kevin Costner’s idea.
I’m not sure — that’s the way it came to me, although I’ve heard it was his assistant that first mentioned the song. Originally they wanted to use “What Becomes of the Brokenhearted.” I did two demos of it for Whitney, drove down both times to downtown L.A. where she was filming. I liked the song but I didn’t feel there was enough meat on the bone for somebody like Whitney Houston to sing. So I wasn’t confident, which probably tainted her response — she didn’t like either one.

Then, lo and behold, the song appeared on the Hot 100 [in a cover by the English singer Paul Young]. I had to feign like I was upset: “Kevin, you’re never gonna guess what happened…” He goes, “OK, lemme think about that,” and next thing I know, he delivers the title “I Will Always Love You” to me.

In those days, you had to go to the record store to hear something. I sent the assistant down there, and she came back not with Dolly’s version but with Linda Ronstadt’s version. And Linda only did two verses, not three, so that’s what I thought the song was. I didn’t know there was a third verse.

We recorded it in Florida, and because I was friends with Dolly — I’d played on a lot of her records — I called her and told her Whitney was doing her song. She said, “Great, I can’t wait to hear her sing that third verse.” I was like, “There’s no third verse.” She said, “What are you talking about? It wraps the whole song up: ‘I wish you joy and happiness.’” So we went back in the studio, and I think that’s when I conjured up the drum moment.

Was the drum moment always tied to a key change?
Oh yeah. When I make records, what I’ve always tried to do is give a record that moment where I imagine the audience leaping to their feet in the middle of the song.

Why a sax solo?
Why not? I had two big No. 1 hits around that time with sax solos — the other was “I Swear” [by All-4-One]. Adam Levine and I were talking about saxes recently because he was playing me something that had sax on it. I said, “Hey, buddy, welcome to the club.”

“I Will Always Love You” spent 14 weeks at No. 1, the longest stretch of all time until —
Mariah.

She and Boyz II Men went 16 weeks with “One Sweet Day.”
That was a little bit deflating. We thought we’d hold the record forever.

A few years ago, Babyface told me, “There’s no other record where somebody put on a better performance than ‘I Will Always Love You.’ That’s game over.” Is he right?
Not for me to say. But it’s certainly up there. I remember when Whitney was doing the a cappella part at the front, I was standing there and her mother was standing beside me. She whispered, “You’re witnessing greatness right now.” And she was right.

I wanted to cut the a cappella part. It was Kevin’s idea. I told him, “For your movie, OK, we’ll do it. But when I finish the record, this is getting axed.” I mean, I didn’t say it quite that boldly. But of course, once she sang, “If I…,” I was like, Oh my God, how could this record ever start another way than that?