Drake Hogestyn, who played John Black, the sturdy and fiercely loyal character who by turns was a spy, private investigator and mercenary, for nearly 40 years on the long-running soap opera “Days of Our Lives,” died on Saturday, a day shy of his 71st birthday.

Mr. Hogestyn had pancreatic cancer, according to a statement from his family shared by the show. He died in Los Angeles, according to a publicist for the show, Andrea McKinnon.

In 1986, Mr. Hogestyn first appeared on “Days of Our Lives,” which premiered in 1965 on NBC and follows various characters in the fictional Midwestern town of Salem. For a few years, he played another character, Roman Brady, but came to be known best for his role as John Black.

Mr. Hogestyn appeared in more than 4,200 episodes of the soap opera and became a fan favorite for his portrayal as the rugged, raspy-voiced and often heroic character who had the skills of an intelligence agent, a police officer and a private investigator.

The character was also known for being married to Dr. Marlena Evans, a psychiatrist and the town’s de facto matriarch, played by Deidre Hall. In 2005, the actors won a Soap Opera Digest Award for Favorite Couple.

After high school, Mr. Hogestyn enrolled at the University of South Florida in Tampa on a baseball scholarship and double majored in microbiology and applied sciences.

After graduating, he was drafted by the St. Louis Cardinals and then the Yankees. He played third base and second base for the Yankees’ lower-level minor league teams in 1976 and 1977 before he chipped his right heel on a pier cement block at the beach, according to MLB.com and Baseball Reference.

Mr. Hogestyn then pivoted to acting. He became best known for playing John Black on “Days of Our Lives.” He played the character through 2009, when his character and Ms. Hall’s were written out of the show because of budget cuts. The actors were eventually rehired in 2011.

“I’ve been through four identity changes, multiple wives and families on the show,” Mr. Hogestyn said of the character in a 2020 interview with MLB.com. “The fire still burns for me. I’m still attached to the character and the show.”

Mr. Hogestyn continued playing the character on NBC when the show moved to the network’s Peacock streaming service in 2022. He most recently appeared on the show in June.

Outside of the soap opera, Mr. Hogestyn’s acting credits included the musical CBS series “Seven Brides for Seven Brothers” in 1982 and some television movies, such as “Beverly Hills Cowgirl Blues” (1985); “Generation” (1985); and “One Stormy Night” (1992).

He is survived by his wife, Victoria; their four children, Rachael, Ben, Whitney and Alexandra; and seven grandchildren.