Four of his novels have been adapted into films of the same names: Clint Eastwood's Mystic River (2003), Martin Scorsese's Shutter Island (2010), and Gone Baby Gone (2007) and Live by Night (2016), both directed by Ben Affleck.

His brother, Gerry Lehane, who is two and a half years older than Dennis, trained at the Trinity Repertory Company in Providence and became an actor in New York in 1990.

Lehane's first novel, A Drink Before the War (1994), which introduced the recurring characters Patrick Kenzie and Angela Gennaro, won the 1995 Shamus Award for Best First P.I.

[13] Lehane called the novel his "great white whale" and said that when he finally finished it, he would "either write a sequel—or take a break from the cops and return to Patrick and Angie.

Marshal Teddy Daniels, "who is investigating the disappearance of a murderess who escaped from a hospital for the criminally insane and is presumed to be hiding on the remote Shutter Island.

In 2010 Lehane published Moonlight Mile, his sixth book in the Patrick Kenzie and Angela Gennaro series, and his first of that genre in 11 years.

He taught fiction writing and serves as a member of the board of directors for the Solstice Low-Residency MFA Program at Pine Manor College in Chestnut Hill, Massachusetts.

As of June 2006, he was living temporarily in St. Petersburg, Florida, and teaching as writer-in-residence at Eckerd (usually during the spring semester), where he also co-directs the Writers in Paradise conference each January.

[23][24] Lehane wrote the teleplay for the episode "Dead Soldiers" from a story by series creator and executive producer David Simon.

[25][26] Lehane made a cameo appearance in the third-season episode, "Middle Ground," as Sullivan, an officer in charge of special equipment.

[27][28] Lehane has commented that he was impressed by the show's creators (David Simon and Ed Burns) having such an ear for authentic street slang.

[29] Lehane returned as a writer for the fourth season in 2006 and wrote the teleplay for the episode "Refugees," from a story he co-wrote with producer Ed Burns.

On November 27, 2012, The Boston Herald reported that Lehane would join the writing staff of HBO's Boardwalk Empire as a writer and a creative consultant.

[40] That same year he was attached to adapt the script for the remake of the critically acclaimed French film A Prophet, a prison drama.

[41] Kenzie & Gennaro series: Coughlin series: Stand-alones: He has won other professional awards and honorary degrees: In Spring 2009, Lehane received the Joseph E. Connor Award and was made an honorary brother of the Phi Alpha Tau professional fraternity at Emerson College in Boston, Massachusetts.

Other brothers and Connor Award recipients include Robert Frost, Elia Kazan, Jack Lemmon, Red Skelton, Edward R. Murrow, Yul Brynner, and Walter Cronkite.