The company said that James is committed to staying at Intel through January to assist with the transition.

In 2014, James landed at number No. 21 on Fortune’s Most Powerful Women list. She’s worked for Intel for 28 years and is the highest-ranking woman in its history.

In her current role James has helped the company move beyond PC and server chips and into newer technologies like mobile computing and wearables. James lost out to Brian Krzanich in the race for the company’s CEO job in 2013, but has remained a vital player, overseeing Intel’s semiconductor manufacturing operations, software and security efforts, human resources, and corporate strategy. In a letter to employees on Thursday, James acknowledged that being passed over for the Intel CEO job factored into her decision to leave. “When Brian and I were appointed to our current roles, I knew then that being the leader of a company was something that I desired as part of my own leadership journey. Now is the right time for me to take that next step,” she wrote.

Earlier this year, James became a leading force in the technology industry’s on-going fight to increase its diversity when Intel announced a $300 million investment in training and recruiting female and other groups of underrepresented computer scientists. Krzanich introduced the investment at the Consumer Electronics Show in January, but it’s James who was in charge of the initiative.

Fortune reported in 2014 that 77% of Intel’s employees were men. “We looked at our numbers and said, ‘look, we’re not bad but the problem is we’re not good enough,’” James told Fortune after the announcement. She said Intel’s plan was to build a pipeline of underrepresented engineers and computers sciences by funding programs to teach STEM skills to young people in underserved areas. At the time, she said the company would collaborate with higher education institutions, invest in women and minority-owned companies, and create bolder hiring and retention incentives to encourage diversity at Intel. The company’s overall goal is have a workforce that reflects actual demographics of women and minorities by 2020, James told Fortune in January.

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In the wake of James’ announcement, Intel spokeswoman Laura Anderson told Fortune on Thursday that “Intel’s commitment to diversity and inclusion and the progress we’ve made remains strong.” Aicha Evans, a vice president and general manager of Intel’s communications and devices group, will take over the diversity campaign. Anderson said that 41% of the company’s hires this year have been “diverse,” versus 32% last year. In the first quarter, 17% of senior hires were underrepresented minorities and 33% were women up from 6% and 19%, respectively, in 2014.

In James’ note to Intel employees detailing her upcoming departure, she said that her decision to leave the company was “difficult.” She wrote, “Intel has been my second family. It is an amazing company that has changed the way people live their lives, and I am proud to have contributed to that in a meaningful way.”