(There are some discrepancies as to which station Maxwell first began working at, but most sources point to WNJR). WNJR was known as the "voice of Newark" during the 1920s and was owned by Herman Lubinsky, the co-founder of Savoy Records. However, at the time Jocko went to work there in 1929, the station was known as WNJ; when that station went defunct, it returned to the air later as WNJR. It is believed by many authors and historians of the radio era that Maxwell became the first African American sports reporter. In fact, the black press of the 1930s and early 1940s regularly asserted that Maxwell was the first and only black sportscaster on radio, although some newspapers qualified it by saying he was the only black sports announcer in the East, or in any major city. Maxwell was broadcasting on stations throughout northern New Jersey, and was also heard in New York City, beginning in the early 1930s. He was a sports commentator at station WHOM in Jersey City, where he hosted a program called Sport Hi Lites, and also reported about area teams. He later hosted a sports report called, "Runs, Hits and Errors" on WRNY, a station based in Coytesville, New Jersey, which had a studio in Manhattan at the Roosevelt Hotel. His reports gradually expanded to include interviews with Negro league baseball players. In 1938, he joined station WWRL, where his "Five Star Sports Final" program became very popular; on it, he interviewed some of the biggest stars in pro sports, including Hank Greenberg, Sid Luckman, and Dixie Walker. By 1942, he had been promoted to the station's sports director. Maxwell later became the public address sports announcer at Ruppert Stadium for the Negro leagues team the Newark Eagles. He initially announced for games only on Sundays. Maxwell continued broadcasting for both games and radio stations until 1967. Maxwell also founded and managed the Newark Starlings, a mixed race, semi-professional baseball team. He also became a contributing writer to Baseball Digest, where he wrote about subjects ranging from the integration of baseball to Jackie Robinson. In 1940, Maxwell authored a book of interviews with players entitled, "Thrills and Spills in Sports". He also submitted stories on the Newark Eagles to the Ledger in Newark, which is the predecessor of The Star-Ledger newspaper. In the 1950s and 1960s, he wrote historical articles about the Negro Leagues; his work was syndicated in a number of black newspapers, thus keeping the players' names alive for a new generation.