PersonaSteer: Dynamic Activation Steering for Personalized Multi-turn LLM Conversations

Sijian Ren, Qingbin Zeng, Bingqiao Gu, Fengli Xu, Yong Li


Abstract
Personalizing Large Language Models (LLMs) for long-term multi-turn interactions remains challenging, as user preferences and behavioral traits are progressively revealed and continuously evolving throughout conversations. Previous personalization methods have mostly relied on prompt-based or post-training (e.g., fine-tuning) paradigms; however, these approaches have been either prone to shallow alignment or have suffered from high computational costs. Inspired by the recent emergence of activation steering, we explore whether personalized alignment can be achieved through lightweight latent-space intervention without modifying backbone parameters. To achieve this goal, we propose PersonaSteer, a dynamic side-model architecture for multi-turn personalized alignment via learnable activation steering. Specifically, to enable fine-grained and evolving personalization, our design learns high-dimensional steering representations from unstructured interaction history and injects them into the backbone model’s residual stream for latent-space behavioral modulation. Furthermore, we introduce a steering-vector feedback loop to maintain persona consistency across multi-turn conversations. Extensive experiments demonstrate that PersonaSteer achieves best or top-tier alignment performance, averaging 3.18/5 on Qwen2.5-7B and 2.95/5 on Qwen2.5-3B. In addition, our framework approach maintains stability during evolving dialogues, with alignment performance consistently improving over time. PersonaSteer provides a lightweight solution for building truly dynamic and personalized LLM. The code is available in https://github.com/tsinghua-fib-lab/PersonaSteer.
Anthology ID:
2026.findings-emnlp.1270
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
26856–26876
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1270/
DOI:
10.18653/2026.findings-emnlp.1270
Bibkey:
Cite (ACL):
Sijian Ren, Qingbin Zeng, Bingqiao Gu, Fengli Xu, and Yong Li. 2026. PersonaSteer: Dynamic Activation Steering for Personalized Multi-turn LLM Conversations. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 26856–26876, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
PersonaSteer: Dynamic Activation Steering for Personalized Multi-turn LLM Conversations (Ren et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1270.pdf