A veteran allocator who managed the Robert Wood Johnson Foundation’s portfolio for 20 years is temporarily coming out of retirement to oversee a New York-based philanthropic organization’s portfolio as it looks to replace its outgoing investment chief.

Brian O’Neil told Institutional Investor he will step in as interim chief investment officer of the Wallace Foundation. Starting in July, the former RWJ CIO will oversee the $1.7 billion portfolio while executive recruiter Spencer Stuart seeks a replacement for departing CIO Tom Lenehan.

A Wallace spokesperson confirmed that Lenehan is leaving the foundation at the end of June to join Euclidean Capital — the family office for late Renaissance Technologies co-founder James Simons — as managing director of investment strategy and co-head of hedge funds. Lenehan took on the role at Wallace in 2021 after longtime CIO Rob Nagel retired.

O’Neil is currently a non-voting member of the Wallace board’s investment committee. He retired from RWJ in 2023 after taking on the CIO position in 2003 and has been an independent consultant since.

An advocate for ESG and DEI, O'Neil prioritized mission-aligned investing at RWJ, enforcing strict exclusions on tobacco, alcohol, and firearms while still pursuing uncorrelated returns. He also favored long-short credit strategies post-2008 for their research-driven upside. At a 2023 webinar sponsored by the Diverse Asset Managers Initiative, he pushed for diversity in emerging managers, acknowledging that private markets' reliance on networks hurt minority talent.

The Wallace Foundation funds research on arts, school leadership, and youth development programs. A spokesperson added that O’Neil’s “alignment with Wallace’s values,” combined with his “strong understanding of” Wallace’s investment approach made him the right person “to support the foundation during this transition period.”

This move follows the Wallace Foundation bringing Jean Desravines aboard as its new president, replacing outgoing foundation head Will Miller. But with Miller and Lenehan set to leave this month and Desravines not joining until September, the foundation did not want a gap with no president or CIO while Spencer Stuart conducted its search.

O’Neil holding down the fort also comes at a time when many foundations and endowments are seeing higher-than-normal turnover with their CIOs. Last month, the MacArthur Foundation tapped the Nature Conservancy’s Bola Olusanya to replace Susan Manske as CIO for its nearly $9 billion endowment. Wallace also joins such institutions as RiceUFICO, and Johns Hopkins that have named new investment chiefs in recent months.

The investor confirmed that he plans to resume retirement once Spencer Stuart does its job and finds a permanent CIO. “I’m 73!” O’Neil said.