Daly City is just over the county line from San Francisco, and it was there that San Franciscans went to indulge in activities banned in their own city. These included gambling, drinking (during Prohibition), dog racing, etc. The San Mateo County authorities often looked the other way, as these vices brought in considerable revenue.

I doubt that boxing was illegal in SF, but betting on the outcome was best done "over the line."

When he wasn't doing comedy.

From Wikipedia:

Billy Murray (April 18, 1892 – March 4, 1926) was an American boxer in the early 20th century.

Although initially starting off rather weak, with 3 wins, 2 losses, and a draw, Murray had an incredible win streak afterwards. He was undefeated his next 49 fights, against boxers such as Anton LaGrave, Johnny McCarthy, Jimmy Clabby, and many others. However, he was defeated twice in a row by a boxer known as George Chip. He won 2 more consecutive fights, and then lost the next 9 fights in a row. He fought 24 more fights afterwards, bringing his record to 60 wins (45 by knockout), 16 losses, and 9 draws.

https://en.wikipedia.org/wiki/Jimmy_Clabby :

Jimmy Clabby (c. 1890 - c. January 1934) was an American boxer. He defeated Tommy Uren in 1917 to win the Australian middleweight championship. He was found dead, of starvation and exposure, at his home in Calumet City, Illinois, near Hammond, in January 1934; in his obituary it was estimated that he had earned and spent over $500,000 during his career as a boxer. He claimed that his usual way to prepare for a fight was "a shave and a drink". He was married and had three children.

Headline of article in NY Times, Jan 20, 1934:

JIMMY CLABBY DEAD; ONCE NOTED AS BOXER; Fought Here, in London and in Australia Squandered Earnings of $500,000

Bill Murray is going fashionable with his longer shorts. Like when Michael Jordan started wearing the longer shorts in 1984. But seriously, 20 rounds? I'm not sure what's going on with all those guys standing in the ring while the fighters mug for a publicity shot. Pre-fight or post-fight? Must be before the fight because they look fresh.

In 1934, Jimmy Clabby was found dead of starvation and exposure at his home in Calumet City, Illinois.

In 1926, Billy Murray died after a six-year bout with tuberculosis, contracted during his service in WWI, in Tucson, Arizona.