The club confirmed the signing Sunday without disclosing financial terms.
Ehrhoff scored 14 points in 49 games for Pittsburgh last season before missing the final 33 games and the postseason due to injuries, including a concussion.
The 33-year-old German is an 11-year NHL veteran who also played for San Jose, Vancouver and Buffalo. He has 327 points in 741 career games.
Los Angeles also is still without two-time Stanley Cup champion Slava Voynov, who is suspended by the NHL and the Kings after pleading no contest to a domestic violence charge.