You’d think the oozy, sweet love songs of Chicago are only enjoyed by an older crowd — those who earnestly listened to “If You Leave Me Now” after a disastrous homecoming dance.

But that’s not the case at all.

Chicago bassist and singer (and Point Loma High graduate) Jason Scheff says when he looks out at the crowd during concerts, he sees plenty of young faces.

“I’m seeing kids who are a generation and a half younger than the music,” he said.

Scheff knows the multigenerational crowds can be attributed to things like the popularity of yacht rock, the genre of mellow ’70s and ’80s music by Michael McDonald, Hall & Oates, the Bee Gees and, of course, Chicago.

“The music comes around in funny little ways,” he said. “There was a TV commercial that used ‘Hard to Say I’m Sorry’ and an Adam Sandler movie that used ‘If You Leave Me Now.’ I think those songs were chosen because they’re classics, they really are like the fabric of our lives.’’

When Chicago performs at Humphrey’s on Tuesday, just a few miles from where Scheff was raised, he expects to perform to some of these newer fans. But he’s also looking forward to seeing family and friends from the old bands with whom he used to perform.

“I love playing at Humphrey’s because it’s so intimate, and I can look out and see my friends from the red, brick church where we used to play,” he said.

Scheff has always been involved with music. His dad is Jerry Scheff, a well-known session bassist who toured with Elvis Presley. Both of his brothers are also songwriters.

Before Scheff joined Chicago in 1985, he was in a wildly popular Top 40 cover band that played every weekend at the Mission Bay Hilton.

It was a dream job, especially since Scheff was only 16 years old. It was a steady gig that paid well and gave the rising singer/songwriter a lot of local attention.

“I really felt like when I was at the Hilton, I’d gone as far as I could in the San Diego music scene,” he said.

Along with the band, Scheff was also enjoying his childhood in Point Loma, especially looking at the hippies sitting on the sea wall at the end of Newport Avenue and then getting sandwiches at Poma’s Italian Delicatessen.

“I went into Poma’s once and said, ‘You have no idea who I am, but your sandwich shop was a huge part of my life,’” he said. “Coming of age in south O.B. in the late 1960s was a really beautiful time. I have such incredible memories.”

Still, those times couldn’t last forever. After two years of playing Kenny Loggins and Kool & the Gang covers, Scheff was ready for more.

So he moved to Los Angeles, mostly so he could “gawk at stars” while looking for gigs. At the time, all his musician friends were signing deals to write songs, so that’s what Scheff concentrated on, too.

His publisher asked him to write material for an upcoming Peter Cetera solo album. Scheff sang the songs himself and played them for management at Warner Bros.

They were impressed, not just by the songs, but by Scheff’s ability to sound just like Cetera.

“Next thing I knew, I got a call from my publisher telling me something big was happening,” he said.

Soon after, Scheff, who was 23 at the time, was asked to replace Cetera.

“It really was like a Hollywood fairy tale,” he said.

Stepping in for one of the country’s most beloved singers was stressful, for sure. But Scheff said he felt more pressure when he joined that Hilton cover band because the musician he replaced was also extremely popular.

“I went through that, on a smaller level, in San Diego,” he said.

Scheff stayed positive and bonded with the band members and its legion of loyal fans.

But he really felt like he understood his role after playing a concert the night after the Sept. 11 terrorist attacks.

“We decided not to cancel,” he remembered. “And at one point when I was singing ‘Feelin’ Stronger Every Day,’ I felt proud and grateful for what I’ve done. I’m not delusional, I know I didn’t record a lot of these songs, but it was an honor to look at the faces and sing those words. I felt like I was helping administer a kind of medicine, and that felt good to me.”