Ryan's big break came when she won a regular role as an extraterrestrial investigator named Juliet Stuart on the TV show Dark Skies. The show was cancelled after one season, but the role had drawn the attention of the science-fiction community.

In 1997, Ryan was cast to play Seven of Nine, a Borg drone freed from the collective on the science fiction series Star Trek: Voyager. The role drew her instant fame and her tight-fitting uniform made her a sex symbol among some science-fiction fans. It also drew criticism from some fans who felt that character was created to add sexuality to the show, and who felt that a disproportionate number of episodes focused on her character to the exclusion of others. Co-star Kate Mulgrew, who played Captain Janeway, reportedly was upset at the addition. However, Ryan's appearance also coincided with higher ratings and more positive critical reviews of Voyager, which were partly attributed to media hype over her addition and better screenwriting. However after this blip the ratings began to slide year by year until the show ended in 2001. Seven of Nine appeared on seven TV Guide covers in the USA.

After Voyager ended in 2001, Ryan joined the cast of Boston Public in the role of Ronnie Cooke, a frustrated lawyer who quits to become a high school teacher. The show's producer, David E. Kelley, wrote the role specifically for her. The show was cancelled in 2004.

Ryan has recently appeared in films, such as Down With Love. Ryan played Lydia in the independent film Men Cry Bullets, with a rave review for her performance from Roger Ebert. Jeri then starred in her first film lead in the indie comedy "The Last Man", playing the last woman on Earth, released by Lion's Gate.

She also had a recurring role as Charlotte Morgan on The O.C. in the autumn of 2005 and guest-starred on David E. Kelley's Boston Legal in 2006. Ryan stars in the new CBS legal drama Shark, playing Los Angeles District Attorney Jessica Devlin opposite James Woods. (wikipedia.org)