Between 1962 and 1967, Lamont and the Holland brothers penned "Heat Wave," the Martha and the Vandellas song that opened at No. 82 on the Billboard Hot 100, staying on the chart for four weeks and peaking at No. 4, "Baby I Need Your Loving," which was performed by Four Tops and stayed on No. 3 for two weeks, and many others.

Lamont and the Holland brothers left the label in 1967 because of a financial dispute. They continued to work together, founding Hot Wax Records and its sister label, Invictus Records, to bring the work of artists like Ruth Copeland, Freda Payne, and groups like the Chairmen of the Board to the mainstream.

"Give Me Just a Little More Time," the debut single of Chairmen of the Board, peaked at No. 3 on the Billboard Hot 100. "Unhooked Generation" by Freda Payne made it to No. 43 on the Billboard Hot R&B Songs chart. "Band of Gold" by Freda Payne entered at No. 93, peaking at No. 3. It was co-written by Lamont, the Holland brothers, and Ron Dunbar.

Lamont split from the Holland brothers in the 1970s because he wanted to focus on his career as a solo artist. He released "Trying to Hold on to My Woman" in 1973. The song promptly made it onto the Billboard Hot 100, peaking at No. 15. "Fish Ain't Bitin" charted at No. 26. Lamont is a two-time Grammy winner. He received a Golden Globe and an Academy Award nomination for the soundtrack of Buster, which he co-wrote with Phil Collins.