Charting in four different decades was an impressive enough achievement, but the way that Robert John did so was particularly noteworthy. He first made the Hot 100 as a 12-year-old in 1958, had to wait until 1968 to do so again, finally had his first top 40 hit in 1972 and his first #1 in 1979, and then had four more songs chart in the 1980s.  
https://www.syracuse.com/entertainment/2025/02/no-1-hit-singer-dies-at-79-charted-in-four-different-decades.html