Nicknamed "Mr. Radio Baseball", Helfer called the play-by-play of seven World Series, ten All-Star Games, and regular season broadcasts for several teams (among them the New York Yankees, Brooklyn Dodgers and Oakland Athletics) and the Mutual and NBC networks.

Helfer was reunited with Barber (who often addressed him on-air as "Brother Al") on the Brooklyn Dodgers broadcasts in 1939.

When he returned the Dodgers job was no longer available, so Helfer started doing "Game of the Day" broadcasts for Mutual.

In 1958 Helfer called Philadelphia Phillies games which were broadcast to the New York market by WOR-TV, helping to fill the void of National League baseball left in the city by the departure of the Dodgers and Giants.

[2] He worked a number of teams after that, including the Houston Colt .45s (1962), Denver Broncos (1962–63), and Oakland Athletics (1968–69).