Hayward went to Buffalo Traditional High School where he was an outstanding basketball player. After graduating from Buffalo Traditional in 2005, Hayward enrolled in Notre Dame Prep School in Fitchburg, Massachusetts, as only the NCAA Division III college SUNY Fredonia expressed any interest in Hayward.
Hayward attended Notre Dame Prep School in Fitchburg, Massachusetts, and while he attended he played with many other notable players, like Michael Beasley (currently playing for the Milwaukee Bucks), Syracuse University standout Paul Harris and UTEP player Derrick Caracter. Hayward started both freshman and sophomore seasons. After Notre Dame Preparatory School Hayward attended Marquette University.
Considered a four-star recruit by Rivals.com, Hayward was listed as the No. 18 small forward and the No. 73 player in the nation in 2006.
At Marquette University, Hayward received the nickname "Money Man". He finished his Marquette career as the program's 2nd all-time leading scorer and 5th all time in rebounds, as well as garnering 2nd-Team All-Big East honors in 2008 and 2010 and Honorable Mention AP All-American status in 2010 while leading Marquette to 4 NCAA Tournament appearances. On April 2, 2010, Hayward was named the Hershey's Player of the Game in the Reese's College All-Star Game.
On June 25, 2010, Hayward was selected by the Washington Wizards with the 30th pick in the 2010 NBA draft, but his draft rights were traded to the Minnesota Timberwolves shortly after being drafted. In 2011, his college teammate Jimmy Butler was taken with the same pick in the NBA draft. It was the first time Marquette players went back-to-back in the first round since Bo Ellis was drafted by Washington in 1977 and Butch Lee was taken by Atlanta in 1978. In his first season in the NBA, he averaged 3.8 points in 10 minutes per game for the Timberwolves. On December 13, 2011, before the start of another season, Hayward was traded to the Oklahoma City Thunder for two second-round draft picks and Robert Vaden.
The Thunder assigned Hayward to the Tulsa 66ers of the D-League on March 2, 2012. The Thunder recalled him on March 4, 2012 after he averaged 28 ppg in 2 games with the Tulsa 66ers. With the Thunder that season, he averaged 1.4 points per game, shooting 34% from the field. Hayward reached the 2012 NBA Finals with the Thunder, but the team lost to the Miami Heat.
On October 27, 2012, Hayward was traded to the Houston Rockets and subsequently waived. On December 31, 2012, Hayward re-signed with the Timberwolves. He was waived by the Timberwolves on January 6, 2013, but re-signed two days later on a 10-day contract. After the 10-day contract expired, he joined the Los Angeles D-Fenders of the NBA Development League. He was waived by the D-Fenders on April 4, 2013 after sustaining an injury.
In September 2013, Hayward signed with the New Orleans Pelicans. He was later waived by the Pelicans on October 13, 2013.
On January 29, 2016, Hayward was reacquired by the Los Angeles D-Fenders.
On November 1, 2016, Hayward was acquired by the Long Island Nets after previously acquiring his rights through the expansion draft. On February 8, 2017, Hayward was waived by the Nets. In 20 games, he averaged 12.5 points, 5.9 rebounds and 1.4 steals in 24.3 minutes.
On February 11, 2017, Hayward signed with the Guaros de Lara of the LPB.