Meta said on Thursday that it planned to invest $14.3 billion in Scale AI, a start-up that works with data to train artificial intelligence systems, in a deal that Meta hopes will add needed muscle to its disappointing A.I. division.

As a condition of the deal, Alexandr Wang, Scale AI’s 28-year-old chief executive, plans to join Meta in a top leadership role in the new division, which Meta is calling its Superintelligence lab. Mr. Wang, whom people inside Meta have taken to calling a visionary leader, will also bring a team of employees from Scale AI to work at Meta.

The move to invest billions in Scale AI, an amount equal to about 10 percent of Meta’s revenue in 2024, would be Meta’s first major minority investment in an outside company. It is Meta’s second-largest deal, after the $19 billion acquisition of the messaging app WhatsApp about 11 years ago.

Meta is scrambling to catch up with A.I. competitors such as Google, Microsoft, OpenAI and Anthropic, as industry executives jockey for an edge in what they believe will be the most transformative technology in a generation.

“Meta has finalized our strategic partnership and investment in Scale AI,” a spokesperson for Meta said in a statement. “As part of this, we will deepen the work we do together producing data for A.I. models, and Alexandr Wang will join Meta to work on our superintelligence efforts.”