He was named president of the Montreal Expos baseball club by Charles Bronfman in 1986, replacing John McHale.

On June 14 1991, he formed a group of thirteen investors to buy the team and prevent a threatened move to Arizona. He paid two million dollars from his own pocket in this purchase.

He was the largest shareholder of the team with 7% of the shares. In 1995, he carried out a "fire sale" of the team's best players, including Marquis Grissom, Larry Walker and John Wetteland.

Brochu refused to play the Canadian National Anthem before an Expos game, so as not to insult Quebec Separatists on their "national day" (June 24).

His plan to save the team from bankruptcy was to build a new stadium in downtown Montreal, which would be named the Labatt stadium.

He asked for subsidies from the Canadian and Quebec governments of the time, but when this attempt failed, he resigned in 1998 and sold his shares to New York businessman Jeffrey Loria.

In 2001, he published the book My Turn at Bat: The Sad Saga of the Expos, which blamed Quebec ex-premier Lucien Bouchard for the sale of the baseball team.