Gary Alan Sinise (Lt. Dan) (born March 17, 1955)is an American actor of stage and screen, as well as a director.

He is a supporter of various veterans' organizations and founded the Lt. Dan Band (named after his character in Forrest Gump), which plays at military bases around the world The Lt. Dan Band is an American cover band originally formed in Chicago in 2003 by Gary Sinise and Kimo Williams to perform at USO shows, entertain troops, and raise money for disabled veterans. The band is named after the character Lieutenant Dan Taylor, whom Sinise portrayed in the film Forrest Gump. Sinise has said in interviews that many people know him by sight as "Lieutenant Dan" rather than by his real name, hence the band's name. The concept came about when Sinise asked for permission to bring musicians on his USO tours. The group was initially known as "Gary Sinise and the Lt. Dan Band".

The Lt. Dan Band has grown from the occasional jam session and Chicago-area gigs to performing for charities and non-profit organizations including the United Service Organizations (USO) and Operation Iraqi Children, the latter of which was co-founded by Sinise in March 2004. In 2011, a documentary was released regarding the band and Sinise's work to benefit veterans. They frequently visit military bases in the United States and abroad, as of February 2019 they have played over 400 concerts.

Sinise was involved in building a memorial to America's three million, living, disabled veterans.  Completed in 2014, the American Veterans Disabled for Life Memorial was built due to the efforts of Sinise and the band championing the cause of the Disabled American Veterans.