As a manager, his most successful period was with the Croatia national team, which he led to the quarter-finals in the 1996 European Championship and won third place at the 1998 FIFA World Cup.

[15] Blažević took over Dinamo Zagreb on 11 December 1980, one of Yugoslavia's big four clubs (the other three being Hajduk Split, Red Star Belgrade and Partizan) in 1980.

After a mediocre first season, in which Dinamo finished fifth, Blažević became an instant club legend in the 1981–82, winning the first Yugoslav league title for the Zagreb outfit after a 24-year drought.

[17] In the 1990s, with Croatia gaining independence, Blažević joined the Croatian Democratic Union (HDZ) and became President Tuđman's admirer and close friend.

Blažević was national team manager from 1994 on a part-time basis, but only a year later it became a full-time job as Croatia faced its first qualifying cycle for the European Championship.

Croatia won the first place in qualifying group, sensationally ahead of Italy and directly entered Euro 96 in England.

From January to June 1996 Blažević took up a position as an advisor at HNK Rijeka to help newly appointed coach Nenad Gračan save his former club from relegation.

[18] Croatia passed group stage with wins against Turkey and current European champions Denmark and loss to Portugal, to face Germany in quarter-finals.

Blažević's Croatia squad for the 1998 World Cup included the likes of Zvonimir Boban, Davor Šuker and Slaven Bilić.

Blažević made a critical coaching decision in that semi-final as he failed to insert his most talented player Robert Prosinečki when the game was in the balance at 1–1.

Blažević retained his position and began to build a new team, filled with younger players for the 2002 FIFA World Cup.

Known as loudmouth and showman, Blažević stayed true to form by claiming he would hang himself from the goalposts if Iran failed to beat Ireland in the deciding qualification playoff for the 2002 World Cup.

In October 2005, he went back to Switzerland and coached Neuchâtel Xamax, replacing Alain Geiger in an attempt to save the club from relegation after they had won just one out of their first ten games of the season.

They were eventually relegated after losing to another Swiss team Blažević had managed 35 years earlier, FC Sion, 3–0 on aggregate, and his tenure there ended in June 2006.

The club experienced a successful 2006–07 season which saw them finish third behind Dinamo Zagreb and Hajduk Split and earned them a spot in Intertoto Cup 2007.

Immediately after the last game of the season, Blažević announced that his stint at NK Zagreb had come to an end by mutual consent between him and the club's chairman.

[24] Since Kodro's dismissal was seen by many fans as the latest in a series of problematic decisions by the much-maligned FA leadership, Blažević was thus, by proxy, not welcomed with open arms by certain sections of the public upon his arrival.

With the national team in complete disarray and many players refusing to even answer call-ups by interim head coach Denijal Pirić, the appointment of Blažević was seen by many fans as FA's desperate makeshift solution designed to appease the public in the wake of the ongoing two-month fiasco by bringing in a fairly established name.

By his own admission, Blažević had already been close to getting the Bosnia-Herzegovina national team job six years earlier in 2002,[25] but ended up not getting hired due to influential FSBiH executive Jusuf Pušina who considered Blažević unsuitable for the job because of the coach's association with the Croatian wartime president Franjo Tuđman and his political party.

[26] Staying true to all the staples of his coaching style from his previous places of employment, seventy-four-year-old Blažević quickly became the media favourite in Sarajevo.

Always ready for a sound bite, he gave bombastic interviews, cheekily delivering bold statements and sweeping promises.

His dismissal was preceded by criticism from Bosnian fans and journalists following Blažević's attack on fan-favorite Zvjezdan Misimović, blaming him for the defeat against Portugal.

[27] After his recession as head coach of the Bosnia and Herzegovina national football team he signed one day later on 12 December 2009 for Shanghai Shenhua.

On 28 August 2011, Iran Pro League side Mes Kerman announced that they will sign a contract with Blažević to replace Samad Marfavi who had resigned two days earlier.

In May 2013 after NK Zagreb failed to secure a place in the Prva HNL and finished at the bottom of the league he announced his retirement from professional football at the end of the season.

Blažević was also a member of the former Croatian president Tuđman's conservative political party HDZ, but he publicly disagreed with his successor, the pro-European centrist politician Ivo Sanader.

[43] During World War II in Yugoslavia, Blažević's two brothers, Anto and Joso, were members of the Ustaše, a fascist organization which ruled Croatia at the time.

[45] During his head coaching tenure with Croatia, Blažević frequently called up Prosinečki as the player became a crucial part of the team and the two seemingly mended fences.

"[47] On 20 October 1995 at Geneva Airport, while waiting to board a flight to Brussels, Blažević was taken into custody by the French financial police on match-fixing and corruption accusations stemming from his time in Nantes.

[48] The arrest occurred as part of a wide-ranging football bribery scandal in France, known in the country as Affaire VA-OM, and was based on former Olympique Marseille director Jean-Pierre Bernès' July 1995 testimony, claiming that FC Nantes head coach Blažević took a ₣420,000 bribe to fix the Marseille vs. Nantes French Division 1 league match on 25 November 1989 that ended in a 0–0 draw.