The group achieved their first taste of success with a local hit titled "Pollyanna" written by Joe South. The band started to attract attention, not only for their soulful sound, but Dennis was one of the few drummers to play while standing up and also singing lead. When the band learned of a New York City group that had a small amount of success with a song titled "Till Then," using the same name, they changed their handle to "The Four Classics" and eventually "The Classics IV".
By 1967, the band had moved to Atlanta, Georgia and were soon approached by Bill Lowery of The Lowery Music Group, who secured a recording contract with Capitol Records. For their first release, guitarist James Cobb and producer Buddy Buie added lyrics to an instrumental called "Spooky", a regional hit for saxophonist Mike Sharpe. After the record's release, it was picked up by a radio station in Louisville, Kentucky and began to get airplay. The song's popularity spread nationally and it climbed to number 3 on Billboard's Hot 100 in early in 1968, although it only reached number 46 in the UK.
Now in demand for TV and live appearances, the group hired drummer Kim Venable and brought Dennis Yost to the front to sing. A follow up song called "Soul Train" failed to match the success of "Spooky", but another tune written by James Cobb and Buddy Buie, "Stormy" shot up the chart to number 5 in 1969, becoming the band's second million seller. Later the same year, they scored a number 2 hit and a third gold record with "Traces Of Love", also written by Cobb and Buie. Touring with the hottest acts of the day, Dennis Yost and The Classics IV scored two more hits in late 1969, a number 12 hit called "Every Day With You Girl" and "Change Of Heart" which reached number 25.
As musical tastes changed, guitarists James Cobb and Dean Daughtry, along with producer Buddy Buie left The Classics IV to team up with some former members of Roy Orbison's back up band. The result was The Atlanta Rhythm Section, who would go on to have an impressive string of hits in the 70s, including two Top 10 records, "So In To You" and "Imaginary Lover" along with their own cover version of "Spooky".
An attempt to feature Dennis Yost as a solo artist never got off the ground and he could only muster minor success with, "Midnight" and "Where Did All The Good Times Go", as he switched labels to Imperial in 1972. One last top forty entry, "What Am I Crying For?" was released on the MGM South label and a final effort, "Rosanna" stalled at number 95 in March of 1973.
Although he could no longer make a hit record, Yost never stopped touring, and continued to appear with the likes of Gary Lewis and The Playboys, Chuck Berry, The Drifters, The Coasters, The Turtles, Paul Revere and The Raiders, Eric Clapton and many others. After moving to Nashville in 1993, he added writing and record production to his list of accomplishments. He currently has twenty-seven published works to his credit and produced Barbara Lewis ("Hello Stranger," "Baby, I'm Yours," and "Make Me Your Baby") on a song called "Donor" to help the cause of organ donation awareness.
At the turn of the millennium, Dennis underwent successful throat surgery for a condition that had severely impaired his singing voice. He also won a trademark dispute which gave him exclusive rights to the name "The Classics IV" for both performing and recording purposes.
In 2005, Yost suffered a fall that was so severe, he was admitted into a nursing home where he could receive constant care. A singer named Tom Garrett was chosen to replace him in The Classics IV, with Dennis believing he could still make the odd special appearance when his health permitted. He sang at one final show on May 16th, 2008, but died of respiratory failure on December 7th of that same year at the age of 65, on the 40th anniversary of when "Stormy" entered the Billboard Top Ten.
The Classics IV continued to tour and were still active in December, 2011.