[5][1] American Billy Peacock fell to Halimi in Paris on March 16, 1956, in a close, strategically fought, ten round points decision.

[6] On April 1, 1957, at the Vélodrome d'hiver in Paris, Halimi became world bantamweight champion by defeating the Italian deaf-mute boxer Mario d'Agata in a fifteen-round decision.

The partisan Parisian crowd of 17,000 watched Halimi take eleven of the fifteen rounds, while D'Agata managed to win only two.

[5] On November 6, 1957, Halimi faced Raul Macias in his second title bout at Los Angeles' Wrigley Field.

Halimi shook Macias with a hook to the jaw in the furious fourth round, though the bout featured no knockdowns.

The pace of the bout was slow, until the sixth when Halimi landed two hard left hooks to the body of Campo.

The pace of the ten round bout displeased the French crowd, but Halimi won the close decision.

Midway through the eighth, Becerra trapped Halimi on the ropes and dropped him with a devastating left hook to the jaw.

[2][15] On October 25, 1960, Halimi defeated Irishman Freddie Gilroy, taking the European Bantamweight Championship in a controversial fifteen round points decision.

Early in the eighth, the crowd of 15,000 watched Caldwell take the lead after leaving a nagging cut over Halimi's eye.

[2][18] Though he was adored in France and his native Algeria, his personal life included questionable friendships, addictive betting, and separation from his wife.

After a cut in the first, Rollo had trouble getting inside, taking a defensive posture, except for the last two rounds when he made a desperate, but futile attempt at the decision.