On April 5, 2005, the series was renewed for a second season, although ABC suspended the series in favor of Grey`s Anatomy. The success of Grey`s Anatomy put Boston Legal on hold until the fall of 2005, when it returned for an extended 27-episode season.   Rhona Mitra and Monica Potter left the show during intermission, while Julie Bowen was cast as Denise Bauer.  Ryan Michelle Bathe and Justin Mentell were then cast as junior partners Sara Holt and Garrett Wells. In the second episode of season 3, Craig Bierko was introduced as Jeffrey Coho and Constance Zimmer as Claire Simms. In episode 11, guest star Gary Anthony Williams joined the cast, Craig Bierko left the cast in episode 15. On June 4, 2007, TV Guide announced that René Auberjonois, Julie Bowen, Mark Valley and Constance Zimmer would not return for season 4.  On 13. In June 2007, it was announced that actor John Larroquette (former guest star of The Practice) would join the cast as a senior partner, who was transferred from the New York offices of Crane, Poole & Schmidt, while actress Tara Summers would join as a young employee. Christian Clemenson (former guest star of The Practice), who had occasionally appeared as Jerry Espenson (a brilliant but socially inept lawyer), was promoted to the main cast.  The production also indicates that René Auberjonois, Mark Valley, Julie Bowen and Constance Zimmer could return in guest roles.  On July 2, 2007, it was announced that René Auberjonois and Mark Valley would return in recurring roles; It was also announced that Taraji P. Henson would join the cast in Season 4, with Saffron Burrows appearing in a recurring role. Burrows later became a full-time cast member.
 The finale of Boston Legal`s two-hour series aired on Monday, December 8, 2008 at 9:00 p.m. (Eastern Time) / 8:00 p.m. (Central Time). David E. Kelley stated in an interview with the Pittsburgh Post-Gazette on December 7, 2008, that it was ABC`s decision to end Boston Legal and that it “had to fight to bring it back for a short 13-episode season.” On November 30, 2004, it was announced that Candice Bergen would join the cast as lead partner Shirley Schmidt, a character that producers had been trying to introduce for several months. Lake Bell left the series in the middle of the season and René Auberjonois was promoted to lead actor. Anthony Heald and Betty White also had regular appearances after appearing as the same characters in The Practice. The American producers of the series also hired British writer and lawyer John Mortimer (creator of the British legal series Rumpole of the Bailey) as a consultant for Boston Legal.  Note: Each U.S. television season begins at the end of September and ends at the end of May, coinciding with the conclusion of the May sweeps. All times mentioned in this section were in the Eastern and Pacific time zones. On May 13, 2008, ABC announced that Boston Legal would return in the fall for a fifth and final season.   Saffron Burrows did not return as a series regular after joining the cast of My Own Worst Enemy. The final season consisted of 13 episodes to reach the “100” mark, which allowed for a successful syndication. There has been speculation that Boston Legal could receive an additional episode order if the series had another strong performance at the Emmy Awards and achieved solid ratings in its new fall window.
The season began airing on September 22, 2008. Before the show`s premiere, it bore the working title of Fleet Street, a reference to the actual street in Boston where the fictional Crane, Poole & Schmidt had their offices. The working title was later changed to The Practice: Fleet Street, but this title was dropped in favor of Boston Legal.  The real building advertised as a law firm is located at 500 Boylston Street, 1.4 miles from Fleet Street. On June 18 and 20, 2008, it was announced that Gary Anthony Williams and Taraji P. Henson would not return as Clarence Bell and Whitney Rome, respectively, for season 5.   On 17. In July 2008, Boston Legal was nominated for seven Emmy nominations, including Best Drama Series for the second year in a row.