Ikuta clerked for Ninth Circuit Judge Alex Kozinski from 1988 to 1989 and for United States Supreme Court Justice Sandra Day O'Connor from 1989 to 1990.

Ikuta is an active member of The Federalist Society, a conservative and libertarian organization which holds panels, debates, and discussions, and she has been known to attend their national events.

[4] Ikuta was nominated to the United States Court of Appeals for the Ninth Circuit by President George W. Bush on February 8, 2006, to fill the seat vacated by Judge James R. Browning, who assumed senior status in 2000.

In the opinion, Ikuta wrote, "Cooperation relating to enforcement of federal immigration law is in pursuit of the general welfare, and meets the low bar of being germane to the federal interest in providing the funding to "address crime and disorder problems, and otherwise... enhance public safety... one of the main purposes for which” the grant is intended.

In her dissent, Judge Kim Wardlaw wrote, "[The Department of Justice's] decision to implement both the illegal immigration focus area and the Cooperation Certification is foreclosed by the text, structure, and purpose of the Community Policing Act.

"[12] On February 24, 2020, Ikuta wrote the majority opinion upholding the Trump Administration rule withholding Title X funding from health-care providers that perform, promote, or support abortion with patients.

The majority relied on the Supreme Court precedent Rust v. Sullivan, which upheld a nearly identical rule during the presidency of Ronald Reagan.