In law school she was one of only two women in her graduating class.
In 1983, Ireland left private practice when she was appointed to the King County Superior Court by Governor John Spellman. Ireland won the subsequent election for a full term on the court, and was re-elected four times. In 1994, she ran for a seat on the Washington Supreme Court, the highest court in Washington. Ireland finished third, with Gerry L. Alexander winning the seat. While on the King County court she was dean of the Washington Judicial College. She spent six years on the superior court judge group's board of trustees and was president for one year of the group. Her further service included a position on the Board for Court Education, and as vice chairperson from 1996 to 1998 of the Board for Judicial Administration. In 1998, the Leadership Institute in Judicial Education awarded her a distinguished service award. Also that year she was also named Judge of the Year by the state trial lawyer's association. While on the court she changed her last name to Ireland. Ireland's mother's maiden name was Janice Marcia Ireland.
In 1998, she ran a second time to join Washington's highest court in a bid to replace the retiring James M. Dolliver. In the primary election she finished first out of seven candidates and faced James Foley in the November general election. Ireland defeated Foley in November and won a six-year term on the court. With the election of Mary Fairhurst in 2002, Ireland became part of the only state Supreme Court at that time to have a majority of women.
Two weeks after her appointment to the bench in 1983, Ireland was rear ended in a car crash and injured her back. After several years of unsuccessful physical therapy, Ireland turned to weightlifting to attempt to permanently fix the back pain. Ireland continued to lift and became a powerlifter, participating in competitions in the US, Europe, India, and South America. She has won five world championships, seven USAPL national championships, and holds 12 world records and 27 American records from three federations.
Ireland chose to speak out about the adoption as a Justice, saying "I wanted to help reduce some of the shame around issues of adoption and let young people know that you can be a birth parent and still go on and have a successful career and a successful life."