[4] He went undefeated in his first 23 fights, with a record of 22-0-1 and won the Pennsylvania State Lightweight Title in a bout against Mike Evens on October 24, 1939, in Philadelphia.

[1] Montgomery won recognition by New York state as Lightweight Champion of the World after beating Beau Jack by a fifteen-round unanimous decision on May 21, 1943.

But Montgomery quickly settled down and scored frequently with a strong straight right that at times had Jack close to a knockout and against which he could find no adequate defense.

[9] On January 25, 1944, Montgomery impressively knocked out powerful Black lightweight Ike Williams in the twelfth round at Convention Hall in Philadelphia.

[1] Montgomery lost to Al "Bummy" Davis at Madison Square Garden in a non-title bout before 17,654 fans in a first-round KO on February 18, 1944.

[1] He retook the title from Beau Jack on March 3, 1944, at Madison Square Garden in a fifteen-round split decision before 19,066 fans.

[12] On February 13, 1945, Montgomery had a fierce bout with Cecil Hudson at the Olympic Auditorium in Los Angeles, California, winning in a ten-round decision.

Montgomery received a furlough from active Army duty at Luke Field Arizona, and had not appeared in a competitive match for four months.

[13][14] He successfully defended his second NYSAC World Lightweight Title against Allie Stoltz before 10,872 fans at Madison Square Garden in a thirteenth-round knockout on June 28, 1946.

The telling blow was a right to Stolz, 2:54 into the thirteenth, but in a decisive win, Montgomery put Stoltz on the canvas as many as five times prior to the final knockout.

[15][16][17] On November 26, 1946, Montgomery defended his NYSAC World Lightweight Title against Wesley Mouzon in an eighth-round knockout at Convention Hall in Philadelphia, Pennsylvania before a substantial crowd, of 12,416.

In their fiercely fought November title match, Mouzon took the first three rounds with speed and jabs, but Montgomery countered with body blows and rights, before ending the bout 2:18 into the eighth with a long left hook.

[19] On February 7, 1947, Montgomery had a difficult loss to Tony Pellone before a crowd of 11,365 at Olympia Stadium in Detroit in a ten-round unanimous decision.

[1][20] He lost the World Lightweight Title for the last time against Ike Williams in a six-round TKO on August 4, 1947, at Municipal Stadium in Philadelphia, Pennsylvania.