Ray Parker Jr. found his groove way before 1984’s mega-smash, “Ghostbusters.”

The R&B-pop vocalist, songwriter and guitarist strummed his way into Motown studios and onto live stages recording and performing with Smokey Robinson, Marvin Gaye, Stevie Wonder and other legends in the late 1960s as a teenager.

A Detroit native and guitar prodigy, Parker brought a signature rhythmic groove to his session work that quickly captured the attention of arrangers, songwriters, artists and musicians.

“For me, I was just trying to play the guitar the best I could to get everybody to like it. Now, in hindsight, it’s becoming, ‘Oh, he was doing great rhythm guitar.’ But at the time, I didn’t really think of it like that. I was just trying to play a guitar part or something that would work on the record,” he said.

Parker revisits his five-plus decades in music through a compelling new 90-minute documentary, “Who You Gonna Call? A Portrait of Ray Parker Jr.,” which premiered Thursday night at Detroit’s Redford Theatre as part of the Freep Film Festival.

Directed by Fran Strine (“Hired Gun”), the documentary “traces Parker’s path from the segregated streets of Detroit in the 1960s to the top of the charts and the Hollywood Walk of Fame, offering a candid look at a complicated artist whose musical legacy is overdue for wider appreciation.”

“That’s what this film is about. I mean, ‘Ghostbusters’ came out, and it was such a huge hit. It just overshadowed everything; people didn’t even know I played the guitar or where I came from,” said Parker, who attended the documentary’s premiere with Strine. (Another screening without Parker will be shown Sunday at Emagine Birmingham 8.)

“They were like, ‘Where did he come from? He was born under a broccoli patch, and he just appeared one day.’ This film actually takes you back and says, ‘There was a lot more going on before that. It didn’t just sprout out of nowhere.’”

Motown to Raydio

Parker’s musical journey started while growing up in Detroit’s Virginia Park neighborhood, which was filled with nearby family and friends. Living in the Motor City also meant experiencing the 1967 riots and being randomly assaulted by police one morning on the way to school.

“Some people would look at Detroit and say it was violent. There was a lot of violence back then, but in the neighborhood houses were close together. Somebody lived upstairs over me in my house, but that also meant your friends were closer together,” said Parker, who’s now 67.

“I had 20 friends just down the street before we went around the block, so we could organize a band and stuff like that. I had a real life growing up – real good stuff, real bad stuff. All of it happened, and all of it shaped who I am today.”

By age 11, Parker traded the clarinet for guitar and quickly honed his craft after breaking his ankle one summer. Those bedroom practice sessions eventually led to performing with Bohannon’s house band at The 20 Grand.

“I think that had everything to do with my career … being able to play with different people and learn and go out and play in clubs or in other people’s backyards or in their basements. Basements are wonderful by the way, and a lot of people around the world don’t have basements,” Parker said.

“They shut out the sound, so you can play loud and get your groove on. It’s a totally different experience here than say in present day lifestyle. I don’t think the same set of events would have happened.”

As a teen, he became part of The Spinners’ touring group, recorded with Smokey Robinson in the legendary Motown Studio A, co-wrote songs with Marvin Gaye and worked for Holland-Dozier-Holland as a session musician.

“Yesterday, we were in Motown’s original Studio A, and I remember the first time I went there Paul Riser called me for a session. I was just excited to be in Motown’s Studio A, and I had been in Motown Studio B and other studios around the city, but I had never been to Studio A. Then, out of nowhere, in walks Smokey Robinson,” said Parker during a Q&A session after Thursday’s documentary premiere.

In 1972, Wonder approached Parker about playing guitar on “Maybe Your Baby” from Talking Book. That initial, fruitful partnership later resulted in Parker joining Wonder’s touring band while Wonder opened for The Rolling Stones.

“My parents were a little upset because I didn’t graduate from college. They wanted me to work at Ford Motor Company and continue the family tradition, but I told them some point later after I bought them a nice home that ‘Hey, I graduated from Wonder University.’ I think that was just as good,” said Parker, who briefly attended Lawrence Technological University and later moved to Los Angeles.

“(Stevie) taught me how to write songs and put it all together, so the songwriting thing I’m going to totally dump in his department. I think he’s the Beethoven or genius of the 20^th century, and I have pretty much the best guy on the planet.”

Parker soon added notable songwriting credits to his roster for Rufus & Chaka Khan (“You Got the Love”), Barry White (“You See the Trouble with Me”), Herbie Hancock (“Doin’ It”) and others. In 1977, he opted to record his own songs with Raydio, which included Vincent Bonham, Jerry Knight and Arnell Carmichael.

“You watch the people that you’re working with. What better training ground than to see how all those people did it? They’re all considered the geniuses, how did they do it? Firsthand, I got to watch in the studio and watch on stage what it is that they were doing so I could emulate that. And if I could just be 5 percent of that, then I’d be OK,” Parker said.

With Raydio, Parker released a string of hits from 1978 to 1981, including “Jack and Jill,” “You Can’t Change That” and “A Woman Needs Love (Just Like You Do),” before embarking on a successful solo career.

Ghostbusters and Beyond

As a solo artist, he added the hits, “The Other Woman” (1982) and “I Still Can’t Get Over Loving You” (1983), to his growing songbook before receiving a life-changing call from director Ivan Reitman to record a song for “Ghostbusters” in 1984.

“It wasn’t even going to be a record; it was just going to be a background thing over 20 seconds of a library scene when a lady comes out and the books fly off. That all happened later, so everything about that song was a total surprise to me as well as the company, the director and everybody. We were all shocked and surprised; it just came out of nowhere,” Parker said.

Parker’s biggest hit, “Ghostbusters,” spent three weeks at No. 1 on the Billboard Hot 100 in August 1984. Thirty-seven years later, the song still resonates across generations and serves as a longtime anthem for “Ghostbusters” film sequels.

“It’s my favorite song, and it puts a smile on everybody’s face. I don’t care what age they are, and kids that are 6, 7 years old should be looking at me like grandpa, but they all want to take a picture with me because they love that I wrote that song,” Parker said.

“It’s made my kids happy, and Lord knows it’s put my kids through college. There’s nothing bad about Ghostbusters. It’s the No. 1 Halloween song every year, and I embrace it. I don’t like to say I’m tired of playing of that. It’s wonderful, and it’s one of the biggest blessings in the world.”

After “Ghostbusters,” Parker released four additional solo albums and continued to write and perform with other artists. By 2016, he met Strine and appeared briefly in “Hired Gun,” a documentary about session and touring musicians.

During a 16-hour flight to Australia, the duo chatted extensively about Parker’s career, which Strine thought would make a captivating story for his next project. Together, they spent two years conducting interviews, collecting stories and compiling footage for what would become “Who You Gonna Call?”

“I had zero vision; I left it to Fran. Just like when somebody hires me to produce a record, I don’t wanna get in the way. I don’t want anybody else to get in the way when I’m doing it, so I don’t wanna get in the way of somebody else doing it. You either gotta trust their vision or not trust them,” Parker said.

“Who You Gonna Call?” features exclusive interviews with a cast of icons, including Wonder, Hancock, Bohannon, Holland-Dozier-Holland, Steve Lukather, Bobby Brown, Clive Davis, Boz Scaggs, and Parker’s wife and four sons.

“They talk about working with me, how I’ve evolved, what kind of person I am and all that kind of stuff. Obviously, Stevie Wonder is in there; he’s my hero. It was great to have him and Holland-Dozier-Holland in there,” he said.

“You’ll see my kids in it, and they get to say their opinion of me. Not quite the same opinion I share. One of my kids even said I was goofy. I thought I was a player when I was younger, and he talks about how goofy I am.”

Despite those familial impressions, Parker remains seriously committed to music with a new album on the way. The album’s release will coincide roughly with the new “Ghostbusters: Afterlife” film, which will come out Nov. 19.

“It’s just a Ray sound; I’m just going back to the good old days of making music for my folks. I’ve got three or three-and-a-half minute songs like I used to have with romantic, clever lyrics. I don’t know who I’ll sell it to, but there are still some of my friends out there,” he said.