Thomas S. O’Neill

Of Counsel

He / Him

Office

Chicago

Phone

+1 312 923 2671


Thomas O’Neill helps clients navigate the rapidly evolving energy industry. Advances in technology, climate urgency, and new customer choices are accelerating regulatory change. Tom’s clients include power generators, utilities, clean-tech startups, and companies that consume large amounts of electricity for their operations. They turn to him for counsel on new laws, switching to greener energy sources or adapting to the energy transition.

With more than 20 years of experience in the energy industry including generation, transmission and development, Tom helps clients see the big strategic picture. When utilities want to develop green substitutes, he helps them consider the legal pathways to enable an orderly transition over time. When producers wish to sell alternatives to utilities, he can help them amend state laws and regulations to facilitate the production and transport of their new product.

Before joining Jenner, Tom was a client of the firm as a business leader at one of America’s leading energy providers. This gives him a unique perspective and advantageous insights. With his strong track record of advocating for policies that enable new clean energy business models, he is the lawyer that companies headed for tomorrow constantly demand.

Every legal challenge supports some business goal for energy clients; sometimes the best legal outcome is not the best overall outcome, and seeing the difference is critical.

Areas of Focus

Credentials

  • Illinois, 1989

  • University of Notre Dame Law School, JD, cum laude, 1989
  • University of Illinois at Urbana-Champaign, BA, honors with high distinction, 1985

Service / Recognition

  • The American Lawyer, Litigator of the Week, Runner-Up, 2025
  • The Best Lawyers in America, Energy Law, 2023, 2026

  • Christopher House, Board Director, 2006-present; Board President, 2016-2019
  • Lookingglass Theatre Company, Board Director, 2011-2020
  • The American Ireland Fund, Regional Advisory Board Director, 2011-present
  • Legal Aid Chicago (formerly Legal Assistance Foundation), Board Director, 2017-2020
  • Leadership Council for Legal Diversity (LCLD), Board Director, 2019-2020; Board Member Emeritus, 2021-present

  • HData Advisory Board, Member

Thomas O’Neill helps clients navigate the rapidly evolving energy industry. Advances in technology, climate urgency, and new customer choices are accelerating regulatory change. Tom’s clients include power generators, utilities, clean-tech startups, and companies that consume large amounts of electricity for their operations. They turn to him for counsel on new laws, switching to greener energy sources or adapting to the energy transition.

With more than 20 years of experience in the energy industry including generation, transmission and development, Tom helps clients see the big strategic picture. When utilities want to develop green substitutes, he helps them consider the legal pathways to enable an orderly transition over time. When producers wish to sell alternatives to utilities, he can help them amend state laws and regulations to facilitate the production and transport of their new product.

Before joining Jenner, Tom was a client of the firm as a business leader at one of America’s leading energy providers. This gives him a unique perspective and advantageous insights. With his strong track record of advocating for policies that enable new clean energy business models, he is the lawyer that companies headed for tomorrow constantly demand.

Every legal challenge supports some business goal for energy clients; sometimes the best legal outcome is not the best overall outcome, and seeing the difference is critical.

  • Illinois, 1989

  • University of Notre Dame Law School, JD, cum laude, 1989
  • University of Illinois at Urbana-Champaign, BA, honors with high distinction, 1985

  • The American Lawyer, Litigator of the Week, Runner-Up, 2025
  • The Best Lawyers in America, Energy Law, 2023, 2026

  • Christopher House, Board Director, 2006-present; Board President, 2016-2019
  • Lookingglass Theatre Company, Board Director, 2011-2020
  • The American Ireland Fund, Regional Advisory Board Director, 2011-present
  • Legal Aid Chicago (formerly Legal Assistance Foundation), Board Director, 2017-2020
  • Leadership Council for Legal Diversity (LCLD), Board Director, 2019-2020; Board Member Emeritus, 2021-present

  • HData Advisory Board, Member

Overview

Thomas O’Neill helps clients navigate the rapidly evolving energy industry. Advances in technology, climate urgency, and new customer choices are accelerating regulatory change. Tom’s clients include power generators, utilities, clean-tech startups, and companies that consume large amounts of electricity for their operations. They turn to him for counsel on new laws, switching to greener energy sources or adapting to the energy transition.

With more than 20 years of experience in the energy industry including generation, transmission and development, Tom helps clients see the big strategic picture. When utilities want to develop green substitutes, he helps them consider the legal pathways to enable an orderly transition over time. When producers wish to sell alternatives to utilities, he can help them amend state laws and regulations to facilitate the production and transport of their new product.

Before joining Jenner, Tom was a client of the firm as a business leader at one of America’s leading energy providers. This gives him a unique perspective and advantageous insights. With his strong track record of advocating for policies that enable new clean energy business models, he is the lawyer that companies headed for tomorrow constantly demand.

Every legal challenge supports some business goal for energy clients; sometimes the best legal outcome is not the best overall outcome, and seeing the difference is critical.

Areas of Focus

Credentials

Admissions

  • Illinois, 1989

Education

  • University of Notre Dame Law School, JD, cum laude, 1989
  • University of Illinois at Urbana-Champaign, BA, honors with high distinction, 1985

Service / Recognition

Awards

  • The American Lawyer, Litigator of the Week, Runner-Up, 2025
  • The Best Lawyers in America, Energy Law, 2023, 2026

Community

  • Christopher House, Board Director, 2006-present; Board President, 2016-2019
  • Lookingglass Theatre Company, Board Director, 2011-2020
  • The American Ireland Fund, Regional Advisory Board Director, 2011-present
  • Legal Aid Chicago (formerly Legal Assistance Foundation), Board Director, 2017-2020
  • Leadership Council for Legal Diversity (LCLD), Board Director, 2019-2020; Board Member Emeritus, 2021-present

Industry

  • HData Advisory Board, Member

Thomas O’Neill helps clients navigate the rapidly evolving energy industry. Advances in technology, climate urgency, and new customer choices are accelerating regulatory change. Tom’s clients include power generators, utilities, clean-tech startups, and companies that consume large amounts of electricity for their operations. They turn to him for counsel on new laws, switching to greener energy sources or adapting to the energy transition.

With more than 20 years of experience in the energy industry including generation, transmission and development, Tom helps clients see the big strategic picture. When utilities want to develop green substitutes, he helps them consider the legal pathways to enable an orderly transition over time. When producers wish to sell alternatives to utilities, he can help them amend state laws and regulations to facilitate the production and transport of their new product.

Before joining Jenner, Tom was a client of the firm as a business leader at one of America’s leading energy providers. This gives him a unique perspective and advantageous insights. With his strong track record of advocating for policies that enable new clean energy business models, he is the lawyer that companies headed for tomorrow constantly demand.

Every legal challenge supports some business goal for energy clients; sometimes the best legal outcome is not the best overall outcome, and seeing the difference is critical.

Areas of Focus

Credentials

  • Illinois, 1989

  • University of Notre Dame Law School, JD, cum laude, 1989
  • University of Illinois at Urbana-Champaign, BA, honors with high distinction, 1985

Service / Recognition

  • The American Lawyer, Litigator of the Week, Runner-Up, 2025
  • The Best Lawyers in America, Energy Law, 2023, 2026

  • Christopher House, Board Director, 2006-present; Board President, 2016-2019
  • Lookingglass Theatre Company, Board Director, 2011-2020
  • The American Ireland Fund, Regional Advisory Board Director, 2011-present
  • Legal Aid Chicago (formerly Legal Assistance Foundation), Board Director, 2017-2020
  • Leadership Council for Legal Diversity (LCLD), Board Director, 2019-2020; Board Member Emeritus, 2021-present

  • HData Advisory Board, Member

Thomas O’Neill helps clients navigate the rapidly evolving energy industry. Advances in technology, climate urgency, and new customer choices are accelerating regulatory change. Tom’s clients include power generators, utilities, clean-tech startups, and companies that consume large amounts of electricity for their operations. They turn to him for counsel on new laws, switching to greener energy sources or adapting to the energy transition.

With more than 20 years of experience in the energy industry including generation, transmission and development, Tom helps clients see the big strategic picture. When utilities want to develop green substitutes, he helps them consider the legal pathways to enable an orderly transition over time. When producers wish to sell alternatives to utilities, he can help them amend state laws and regulations to facilitate the production and transport of their new product.

Before joining Jenner, Tom was a client of the firm as a business leader at one of America’s leading energy providers. This gives him a unique perspective and advantageous insights. With his strong track record of advocating for policies that enable new clean energy business models, he is the lawyer that companies headed for tomorrow constantly demand.

Every legal challenge supports some business goal for energy clients; sometimes the best legal outcome is not the best overall outcome, and seeing the difference is critical.

  • Illinois, 1989

  • University of Notre Dame Law School, JD, cum laude, 1989
  • University of Illinois at Urbana-Champaign, BA, honors with high distinction, 1985

  • The American Lawyer, Litigator of the Week, Runner-Up, 2025
  • The Best Lawyers in America, Energy Law, 2023, 2026

  • Christopher House, Board Director, 2006-present; Board President, 2016-2019
  • Lookingglass Theatre Company, Board Director, 2011-2020
  • The American Ireland Fund, Regional Advisory Board Director, 2011-present
  • Legal Aid Chicago (formerly Legal Assistance Foundation), Board Director, 2017-2020
  • Leadership Council for Legal Diversity (LCLD), Board Director, 2019-2020; Board Member Emeritus, 2021-present

  • HData Advisory Board, Member

Overview

Thomas O’Neill helps clients navigate the rapidly evolving energy industry. Advances in technology, climate urgency, and new customer choices are accelerating regulatory change. Tom’s clients include power generators, utilities, clean-tech startups, and companies that consume large amounts of electricity for their operations. They turn to him for counsel on new laws, switching to greener energy sources or adapting to the energy transition.

With more than 20 years of experience in the energy industry including generation, transmission and development, Tom helps clients see the big strategic picture. When utilities want to develop green substitutes, he helps them consider the legal pathways to enable an orderly transition over time. When producers wish to sell alternatives to utilities, he can help them amend state laws and regulations to facilitate the production and transport of their new product.

Before joining Jenner, Tom was a client of the firm as a business leader at one of America’s leading energy providers. This gives him a unique perspective and advantageous insights. With his strong track record of advocating for policies that enable new clean energy business models, he is the lawyer that companies headed for tomorrow constantly demand.

Every legal challenge supports some business goal for energy clients; sometimes the best legal outcome is not the best overall outcome, and seeing the difference is critical.

Areas of Focus

Credentials

Admissions

  • Illinois, 1989

Education

  • University of Notre Dame Law School, JD, cum laude, 1989
  • University of Illinois at Urbana-Champaign, BA, honors with high distinction, 1985

Service / Recognition

Awards

  • The American Lawyer, Litigator of the Week, Runner-Up, 2025
  • The Best Lawyers in America, Energy Law, 2023, 2026

Community

  • Christopher House, Board Director, 2006-present; Board President, 2016-2019
  • Lookingglass Theatre Company, Board Director, 2011-2020
  • The American Ireland Fund, Regional Advisory Board Director, 2011-present
  • Legal Aid Chicago (formerly Legal Assistance Foundation), Board Director, 2017-2020
  • Leadership Council for Legal Diversity (LCLD), Board Director, 2019-2020; Board Member Emeritus, 2021-present

Industry

  • HData Advisory Board, Member

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