For the better part of 20 years Bronco Horvath played professional hockey in the NHL, AHL and WHL. After a successful junior career with the Galt Black Hawks, Horvath turned pro with Grand Rapids of the EAHL.
He had toiled in the minors for several years, wondering if he was ever going to get the chance at cracking the NHL. It was thanks to a strong season in 1954-55 with the Edmonton Flyers of the WHL that his opportunity came about. In 67 games, Horvath potted 50 goals and 110 points. In the summer of 1955, Horvath and Dave Creighton were sent to the New York Rangers by the Detroit Red Wings in exchange for Billy Dea, Aggie Kukulowicz and cash. Horvath suited up for 66 games with the Rangers in 1955-56, scoring 12 goals and 29 points.
During his long career, Horvath also made brief stops in Montreal and Toronto but is best remembered for his days as a Boston Bruin where he produced his best offensive numbers. Joseph "Bronco" Horvath centred Johnny Bucyk and Vic Stasiuk on the Boston Bruins' famed Uke line, so named for its players' Ukrainian heritage. The Uke Line combined for 174 points in 1957-58, as Horvath lead the Bruins with 30 goals and 66 points. He added five more goals in 12 playoff games as Boston advanced to the Stanley Cup finals before losing to Montreal. Horvath missed the first 25 games of the 1958-59 season because of a broken jaw, but returned to score 19 goals in just 45 games.
In 1959-60, Horvath battled Bobby Hull all season long for the NHL lead in goals and points. They tied at 39 goals, but Horvath lost the Art Ross Trophy by a single point, collecting 41 assists to Hull's 42. Horvath was named to the NHL Second All-Star team behind Jean Beliveau at centre that year. Never shy about offering his opinion, Horvath was once quoted as saying "If Chief (Bucyk) hadn't got injured, I'd have shattered 50 goals. I'd love to be able to play hockey today with Bucyk and Stasiuk on the wings. I'd score over a 100 goals a year with the 80 game schedule."
By the mid 1960s, Horvath had become a regular minor-leaguer with the Rochester Americans after becoming the property of the Toronto Maple Leafs. Expansion in 1967-68 gave Horvath one last crack at the NHL, when at the age of 37 he appeared in 14 games with the Minnesota North Stars. Horvath also had the distinction of being the property of each of the Original Six NHL clubs at one time or another.
Bronco retired in 1970 from Rochester and joined the Minnesota as a scout. Later he coached in the OHA for the London Knights, and in Cape Cod for semi-pro organization, from where he launched a successful cleaning business.