Born in Bijeljina, SR Bosnia and Herzegovina, Smajić began his career in his local town with FK Radnik Bijeljina. In 1979 Radnik reached the 1/8 finals of the Yugoslav Cup with Smajić being part of the team and that sealed him a move to Belgrade to play in FK Partizan. He made his senior debut with Partizan in the 1979–80 Yugoslav First League. He played 9 consecutive seasons with Partizan, where he won 3 Yugoslav championships. Whilst at Partizan he represented Yugoslavia at the 1984 Summer Olympics in Los Angeles where they reached the semi-finals before being eliminated by France. Later, in 1987 he also debuted for the main Yugoslav national team.
Period in Switzerland
In 1988, he moved abroad to Neuchâtel Xamax who had just won the two previous editions of the Swiss Nationalliga A. Neuchâtel Xamax failed to win the title during the time Smajić played, and all they managed was to be runners-up of the Swiss Cup in 1990. He played there for almost five years before joining FC Basel in the winter break of the 1992–93 season. He played with Basel for the following 4 years, and then he moved to BSC Young Boys in the winter break of the 1997–98 season. He eventually took up a player-manager role in 1998. He was sacked at the end of the season and he also retired from playing.
International career
After representing Yugoslavia at the 1984 Olympics, Smajić later became an A international for the Yugoslav national team. Between friendly games, and qualifiers for the 1988 UEFA European Championship, he had made 4 appearances and scored one goal, between 1986 and 1987. Almost a decade later, and after the break-up of Yugoslavia, he became part of national team of Bosnia and Herzegovina, making two appearances in 1996. Smajić was given an emotional farewell in what was likely his last appearance for the Bosnian national team on 25 April 2000 in Sarajevo, a 0–1 result in a friendly against FIFA All Stars.
Managerial career
Throughout his managerial career, Smajić didn't manage many teams. From 1998 to 1999 he was the player-manager of BSC Young Boys, from 2001 to 2002 head coach of the Bosnia and Herzegovina U21 national team, from 2003 to 2004 manager of Yverdon-Sport FC and for a short time in 2004, from April to June, manager of FC Sion. It wasn't until 2011 that Smajić got his next managerial duty, being the Yverdon-Sport assistant manager to Italian manager Vittorio Bevilacqua. In 2014 he came back to Sion, becoming an assistant to German manager Jochen Dries. After Dries got sacked in December 2014, Smajić took over as new manager of the Sion II team. He managed the II team until September 2015. In June 2018, Smajić was named as the new team manager of Premier League of Bosnia and Herzegovina club FK Sloboda Tuzla, while Milenko Bošnjaković became the new manager of Sloboda. On 13 July 2018, only eight games before the start of the season, Smajić decided to leave Sloboda, stating that because of his back issues he needed to get a back surgery in Switzerland. On 10 June 2019, one year after leaving Sloboda, he came back to the club and became its new team manager, signing a one-year contract. Shortly after, Mile Lazarević was announced as the new manager of Sloboda and worked alongside Smajić. On 1 October 2019, a few days after Lazarević resigned from his managerial position, Smajić also decided to resign from his position and leave Sloboda for a second time.
