Darius Songaila started his basketball career with Lietuvos rytas Marijampolė in second-tier Lithuanian league, the LKAL in 1995. In 1997, he moved to USA where he attended the New Hampton School in New Hampton, New Hampshire. Songaila played the Nike Hoop Summit in 1998. He was also named to the All-European Under-22 Championship 2nd Team.
Darius Songaila played college basketball at Wake Forest University. He was named 3rd Team All-ACC in 2000 and 2nd-Team All-ACC in 2002. He was also named Honorable Mention All-American by the Associated Press as a senior.
Songaila was selected with the 50th pick of the 2002 NBA draft by the Boston Celtics, who eventually dealt his rights to the Sacramento Kings.
He joined CSKA Moscow for the 2002–03 season and won the Russian Basketball Super League. He signed with the Kings in June 2003, and averaged 6.1 points and 3.7 rebounds in 154 games (28 starts) over two seasons.
Songaila signed a one-year deal with the Chicago Bulls in September 2005. He had his most successful season yet with the Bulls, averaging 9.2 points and 4.0 rebounds in 62 games (7 starts). However, he suffered an ankle injury in March 2006 and missed the final 20 games.
On July 17, 2006, Songaila signed with the Washington Wizards. The deal reportedly was worth 23 million dollars over five years. He missed the first 45 games after a surgery for a herniated disc and averaged 7.6 points and 3.6 rebounds in 37 games (1 start).
Songaila eventually became a big part of the Wizards' bench and an occasional starter. He averaged 6.2 points and 3.4 rebounds in 2007–08. At the end of the 2008–09 season, Songaila became a starter because of the injuries suffered by teammates Brendan Haywood and Andray Blatche. He started a career-high 29 games and averaged 7.4 points and 2.9 rebounds.
On June 23, 2009, he was traded to the Minnesota Timberwolves along with Oleksiy Pecherov, Etan Thomas, and a first-round draft pick for Randy Foye and Mike Miller.
On September 9, 2009, he was traded to the New Orleans Hornets along with Bobby Brown in exchange for Antonio Daniels and a 2014 second-round pick.
On September 23, 2010, he was traded to the Philadelphia 76ers along with rookie forward Craig Brackins in exchange for Willie Green and Jason Smith. Songaila had career lows with the 76ers, notably in points (1.6 ppg). With the 2010–11 NBA season coming to an end, he became an unrestricted free agent.
In July 2011, he signed a one-year contract with Galatasaray in Turkey worth $1.5 million.
In March 2012, several weeks after leaving Galatasaray, Songaila signed with Blancos de Rueda Valladolid. Later that year, he signed with BC Donetsk.
On October 8, 2013, he signed with Lietuvos rytas Vilnius for one season. On July 22, 2014, he signed a one-year deal with Žalgiris Kaunas.
At the end of the season, he retired from the professional basketball.
Note: The EuroLeague is not the only competition in which the player participated for the team during the season. He also played in domestic competition, and regional competition if applicable.
On August 5, 2015 Songaila was appointed as an assistant coach for Žalgiris Kaunas.