Answer by taking a quote from the following article:

Conacher was born in Toronto, Ontario on May 24, 1900. His middle name was given after the South African city of Pretoria, where British troops were fighting the Boer War at the time of his birth. He was the eldest son of Benjamin and Elizabeth Conacher, and the third of ten children overall. He had four brothers and five sisters.

Conacher scored the first goal in Pirates history on American Thanksgiving Day Thursday November 26, 1925, against the Boston Bruins. He scored nine goals in 33 games in 1925-26, then returned to Toronto to play professional baseball with the Toronto Maple Leafs. An outfielder on the team, Conacher and the Maple Leafs won the International League championship then defeated the Louisville Colonels to win the Little World Series.  He returned to Pittsburgh for the 1926-27 NHL season, but was dealt early in the year to the New York Americans in exchange for Charlie Langlois and $2,000. The trade nearly proved disastrous for Conacher. He scored 8 goals in 1926-27 and improved to 11 in 1927-28, but playing for a team owned by notorious bootlegger Bill Dwyer resulted in his becoming a heavy drinker. Conacher served as player-coach in 1929-30, but his play and health had deteriorated. Two events in that off-season saved Conacher: he swore off alcohol completely upon the birth of his first child, and his playing rights were sold to the Montreal Maroons.  Conacher periodically struggled with Montreal, and at one point was placed on waivers with no other team willing to take over his contract. Nonetheless, his overall play and point totals increased for three consecutive seasons with the Maroons, peaking at 28 points in 1932-33. He was named to the Second All-Star Team that season, but was traded to the Chicago Black Hawks in exchange for Teddy Graham. Conacher was a key figure in the club's first-ever Stanley Cup victory that season. He finished second to the Canadiens' Aurel Joliat in the voting for the Hart Trophy and earned a spot on the NHL's First All-Star Team.  On Wednesday October 3, 1934, Conacher was involved in one of the largest transactions in league history. He was dealt to the Montreal Canadiens, along with Leroy Goldsworthy and Roger Jenkins in exchange for Montreal superstar Howie Morenz, Lorne Chabot and Marty Burke. The deal was only part of a series of trades involving four teams that represented one of the biggest deals in NHL history. Immediately following the Chicago trade, Conacher was sent back to the Maroons, along with Herb Cain, in exchange for the rights to Nelson Crutchfield. Conacher spent his last three NHL seasons with the Maroons and won his second Stanley Cup in 1935. He ended his hockey career after the team was eliminated from the playoffs by the New York Rangers on April 23, 1937. That final year he was runner-up to Babe Siebert in the 1937 Hart Trophy voting and was placed on the NHL Second All-Star Team.

How did his professional career begin?
Conacher scored the first goal in Pirates history on American Thanksgiving Day Thursday November 26, 1925, against the Boston Bruins.