Upon leaving school he enlisted with the United States Air Force, in which he served with the rank of Airman Second Class.

[5] He began boxing on the Golden Gloves amateur circuit, and also took part in competitive inter-service matches for the U.S. Air Force.

[3] Foster started his professional career on the night of March 27, 1961, against Duke Williams, in Washington, D.C., winning by knockout in two rounds.

In his tenth bout, he made his first of multiple forays into the heavyweight division, and suffered his first loss, at the hands of Doug Jones, by a knockout in the eighth round.

After two more wins, he went in 1963 to Peru, where he lost to South American champion Mauro Mina by a decision in ten rounds at Lima.

One month after knocking out Don Quinn in the first round, he stepped up in the ring again and faced former world title challenger Henry Hank.

At Madison Square Garden in New York, on the night of March 24, Foster became world champion by knocking out Dick Tiger in four rounds.

He ended that year defeating Vick again, and his future world title challenger Roger Rouse, both by a knockout.

It also happened in the 21st century, when Kendall Holt was dropped twice, only to knockout Ricardo Torres in round 1, for the WBO 140 lb title.

After defeating Hal Carroll by a knockout in four rounds to defend his crown, the WBA stripped him of the title, but he was still recognized by the WBC as a champion.

Foster became enraged at the WBA, which proceeded to have Vicente Rondon of Venezuela and Jimmy Dupree fight for the world title.

Rondon won, becoming the second Latin American world light-heavyweight champion (after José Torres), and Foster set his eyes on him.

Foster went on defending his WBC title, and he defeated challengers Ray Anderson, Tommy Hicks, and Brian Kelly.

Their second fight had a distinct social impact because it was fought in apartheid-ruled South Africa, Foster being Black and Fourie being White.

In the mid-1970s Foster became a police officer with the Bernalillo County Sheriff's Department, later becoming a detective and a well known policeman in Albuquerque, New Mexico.