Before finishing his career in April 1949 orthodox boxer Welch built up a record of 109 wins, 6 draws, and 26 losses, starting at age 17 on May 1936 and ending 12 years later at . Welch's longest win streak is 18 fights between May 1936 and October 1938. His longest KO streak in his 141 fights is 8 fights long.
Welch's pro career began against Ted Gagne (0-1-1) in a 3 round contest. Welch got the PTS win via a judges decision. Welch continued his mostly successful career with numerous fights following his debut against boxers including Sal Canata, Dom Labbe and Tommy Reagan. Fights included fighting 9 times in 1936, 10 times in 1937 and 50 times between 1938 and 1941.
Welch went into his next fight against Frisco Dick on October 1st, 1936 with a career record of 6 wins. Coming into the fight with high confidence Welch fought his next fight against Frisco Dick on October 1st, 1936. Unfortunately, Welch was outclassed and lost the decision on the judges scorecards taking his record to 6-1-0. Welch's win streak of 6 rose to 9 following 3 wins against boxers such as Bobby Woolwich, Frisco Dick and Newt Cole.
Welch lost to Lee Anderson in his next fight. Taking place on January 1st, 1937, Welch's career record after this fight stood at 9-3-0. Lee Anderson became the first person to stop Welch. The win came via TKO in the 2nd round of a 4 round bout. Fights against boxers including Tommy Reagan, Dave White and Johnny Lawless followed where he won 15 fights taking his winning streak to 23 wins.
Welch entered his next fight with a mostly successful record of 23-4-1 and took this to 24 wins with a win against Jimmy Mcdougal on March 24th, 1938 via TKO. Welch's fight against Jimmy Mcdougal came in the 3rd round of a 8 round fight via TKO. Welch became the first person to stop Mcdougal. Welch then went on to win a further 49 fights taking his record to 65 wins, 11 losses and 2 draw.
Pushing his career further, Welch fought Izzy Jannazzo on November 14th, 1941 adding to his winning record. Welch was the 2nd person to stop Izzy and he did it in the 7th round via KO. Fights against boxers including Ralph Zannelli, Sonny Horne and Ralph Zannelli followed where he won 56 fights taking his winning streak to 106 wins.
Taking a knock to his career, Welch fought and was defeated by J. C. Wilkins on December 7th, 1948 taking his record to 106-24-6. Welch was beaten by J. C. Wilkins in the 6th round. Welch had only ever been stopped 5 times previously in his career.
Welch's next defeat of his career came against Jose Contreras on April 5th, 1949. This was a challenging final career fight for Welch, Welch was taken the full 10 rounds in a PTS loss. Welch's career ended in a records of 109 wins,26 losses, and 6 draws.