The Team

The Greenstone Team

Jason St. John

Founding Partner

Jason St. John is a Founding Partner of Greenstone Partners and serves as a director of investment sales. Prior to co-founding Greenstone Partners, Jason was a Senior Associate in Marcus & Millichap's Downtown Chicago office for nearly six years where he earned the distinction as a Top 20 National Office & Retail Investment Sales Broker. Over the past decade, Jason has closed transactions in aggregate value of nearly $450,000,000, while also acting as a mentor to the brokerage team.

Jason is active in a variety of charitable organizations, including Imerman Angels, a not-for-profit, one-on-one cancer fighter/survivor matching organization, where he has been an active board member for five years and previously served as its President of their Professionals Board. Jason grew up in both Michigan and Iowa. In his free time, Jason can be found on the golf course, pool, bike path, camping or hiking.

Jason attended Central Michigan University, graduating with a Bachelor’s Degree in Business Administration. He is a licensed Illinois Real Estate Broker and an active member of the International Council of Shopping Centers.

Peter Weitz

Founding Partner

Peter Weitz is a Founding Partner at Greenstone Partners and serves as a director of the advisory and investment divisions and is also the company's managing broker. Peter founded the predecessor to Greenstone Partners, Greenstone Asset Management in 2010. While at Greenstone Asset Management, Peter specialized in structuring joint-ventures and investment sales. His experience within the public and private equity markets provides clients with unique insight in evaluating investment and strategic business decisions.

Peter is a proud Chicagoan, born and raised. Currently, he resides in the Lincoln Park neighborhood with his wife Jen where they are active in local community and charitable organizations. In his free time, Peter can be found traveling, cycling, hiking or boating. Peter is also a loyal Bears fan and season ticket holder.

Peter graduated with a degree in Finance from the University of Illinois at Urbana-Champaign. Peter is an active member of the International Council of Shopping Centers and Building Owners and Managers Association of Chicago.

Leo Solarte

Founding Partner

Leo Solarte, MSRE, is a Founding Partner of Greenstone Partners and serves as a director of retail investment sales and leasing services. Prior to co-founding Greenstone Partners, Leo was the Vice President of Investment Sales for First Western Properties, Inc. Leo played a key role in First Western’s rapid growth and brand recognition for all sales activities including acquisitions and dispositions along with landlord and tenant representation.

Leo has been recognized with ten distinct industry awards for this work in retail real estate since 2010. Leo was made an Honoree of the National Association of Realtors' 30 Under 30 Class of 2012. Leo has also been recognized as a CoStar Retail Power Broker for four years and as a Top Retail Leasing & Sales Agent annually since 2010 by the Chicago Association of Realtor’s Commercial Forum.

Leo is a CCIM candidate and earned his Master's of Science in Real Estate at Roosevelt University where he was a Joseph Freed Tomorrow's Leader in Real Estate Scholarship recipient. Leo received his Bachelor’s Degree in Finance with a minor concentration in Economics from Roosevelt University.

Born and raised in Chicago, Illinois, Leo’s hobbies include boxing, exploring his hometown and spending time with his two sons. Leo is active in several charitable endeavors and is an Advisory Board Member for the Marshall Bennett Institute of Real Estate at Roosevelt University. Leo is an active member of the International Council of Shopping Centers and holds an Illinois Real Estate Broker license.

Danny Spitz


Danny Spitz joined Greenstone Partners as a Partner and director of investment sales. With over thirteen years of experience as a commercial real estate broker and two years as an underwriter for commercial lending at a large Chicago bank, Danny has honed the skills necessary to serve all client types and competently analyze any real estate product type. In his career, Danny has professionally worked on development land, office buildings, mixed-use assets, retail strip centers, apartment towers, self-storage and grocery anchored shopping centers. Prior to Greenstone Partners, Danny was a Managing Director of Investment Sales with Baum Realty Group. During that tenure, Danny completed transactions valued at over $500,000,000. Prior to Baum, Danny spent five years at @properties Commercial, where he pioneered the commercial division of the company and specialized in investment sales and retail leasing.

Danny graduated Cum Laude from Arizona State University’s W.P. Carey School of Business with Bachelor’s Degree in Finance. He is a licensed Illinois Real Estate Broker and an active member of the International Council of Shopping Centers.

Born and raised in in Skokie, Illinois, Danny‘s hobbies include concerts, traveling and playing a variety of sports, including basketball and golf. In his free time, he enjoys activities with his wife and raising his two young children. He is a former Vice President of Chicago Association of Realtors Commercial Forum, a former director of Young Real Estate Professionals, and is currently active with various charitable organizations, including JUF. Danny is a member of the International Council of Shopping Centers and holds an active Illinois Real Estate Broker license.

Greg Dietz


With a focus on Chicagoland investment sales, Greg Dietz joined Greenstone Partners as a Partner and as a director of investment sales. Greg has closed 100+ transactions representing institutions, generational property owners, family offices, private individuals, REITs and real estate funds. With a real estate finance background and deep market knowledge, Greg exhibits the key disciplines to navigate even the trickiest transaction. Greg has completed assignments on mixed-use projects, parking garages, development land, retail strip centers, apartment towers, grocery anchored shopping centers, loft office, flex industrial and single-tenant net leased assets.

Prior to Greenstone, Greg Dietz helped reinvigorate the investment sales group at Baum Realty Group. Before joining Baum, Greg worked in acquisitions, asset management, dispositions and leasing for Tishman Speyer Properties. In one of Chicago’s largest real estate deals ever, Greg was part of the team that purchased the former Equity Office downtown portfolio for $1.72 Billion. Greg also helped manage a portfolio of over 10 million square feet, which included roles in finance, performing hold/sell analyses and negotiating leases.

Greg has experienced 55+ countries including a 14-month backpacking trip with his wife. In between the occasional country music concert and camping trip, he enjoys raising his three children in Wicker Park.

Greg studied Real Estate Finance at Indiana University and grew up in Cincinnati, Ohio. He is a licensed Illinois Real Estate Broker and an active member of the International Council of Shopping Centers. Greg also sits on Wicker Park Committee’s Preservation & Development subcommittee.

Jonny Lefko

Vice President

In a short period of time, Jonny Lefko has established himself as a premier retail investment sales broker beyond Illinois having closed transactions in several states, including Missouri, Kansas, Nebraska, Ohio and California. As an Associate with Greenstone Partners, Jonny specializes in advising clients in the acquisition and disposition of single-tenant net leased assets, multi-tenant strip centers and grocery-anchored shopping centers.

Jonny grew up in Prairie Village, Kansas. He is an avid sports fan as both a participant and spectator and enjoys traveling.

Jonny is a licensed Illinois Real Estate Broker and a member of both the International Council of Shopping Centers and Young Real Estate Professionals. Jonny interned with Greenstone Partners prior to graduating from Michigan State University with a Bachelor’s Degree in Finance.

Brewster Hague


Brewster Hague joined Greenstone Partners as a Vice President of investment sales in 2019. Prior to
joining Greenstone Partners, Brewster spent five years at Marcus & Millichap as a lead Chicago sales
broker of urban retail and mixed-use properties. Throughout his tenure, Brewster has worked on the
acquisition and disposition of retail, multifamily, mixed-use, and development opportunities in Chicago.

Born and raised in River Forest, Illinois, Brewster is a beloved Chicago Bears fan and in his free time he
can be found at Soldier Field on gamedays, on a golf course, discovering new restaurants, or traveling.

Brewster graduated from Marquette University with a double major in finance and real estate. During his
years there, Brewster served as the captain to Marquette University’s Commercial Real Estate Team.
Brewster is a licensed Illinois Real Estate Broker and an active member of the International Council of
Shopping Centers.

Michael Gendell

Associate, Investment Sales

Michael Gendell, raised by a family rooted in real estate, has wasted no time applying his teachings with Greenstone Partners. Before joining Greenstone Partners, Michael was a successful broker at CBRE, as a part of their retail investment sales team. He was responsible for underwriting, business development, and client relations while his insight and energy made him a substantial resource. Prior to joining CBRE, Michael spent two years at Chicago Apartment Finders as a Leasing Agent, where he led the company in sales. He also worked at Marc Realty and with the Chicago Bulls in Community Relations.

Growing up in Glencoe, Illinois, Michael is an outdoor enthusiast who enjoys playing golf, basketball and softball. He is active with several causes including Maggie's Place, Elyssa's Mission, JNF and Chicago Bulls Charities.

Michael graduated from DePaul University with a degree in Organizational Communications and is a member of the West Town Builders Club. He is a licensed Illinois Real Estate Broker and an active member of the International Council of Shopping Centers.

Kyle Winston

Investment Analyst

Kyle Winston joined Greenstone Partners as an Investment Analyst and works with the Investment Sales team in valuing office and retail assets. He is responsible for underwriting and financial modeling, and also works hand in hand with the management team in various functions including budgeting and reporting.

Kyle was born and raised in Prairie Village, Kansas and graduated from the University of Kansas with a Bachelor’s Degree in Finance and a Concentration in Entrepreneurship. He has a passion for both watching and participating in a variety of sports including golf, basketball and baseball. Additionally, in his free time he enjoys cooking and traveling with his family and friends.

Debbie Rogo

Property Administrator

Debbie Rogo has over 15 years of property management experience. With a specialization in commercial real estate asset management. Debbie has held roles as the District Manager for several self-storage firms including Storage USA and Extra Space Storage.

As a property administrator with Greenstone, Debbie is responsible for overseeing all leases in the asset management portfolio. She also tracks all financial aspects of leases including rent schedules, sublease payments, lease renewals, taxes and property expense reimbursement.

A dynamic and achievement focused leader, Debbie is skilled in identifying innovative solutions that improve the team’s asset management performance. She is a results-oriented manager that produces superior results through leadership, effective team work and exceptional customer service.

Debbie grew up in Manassas, Virginia and attended George Mason University. Debbie is a history and archeology buff and enjoys spending time with her grandchildren. Texas hold ‘em, baking and playing the accordion are some of Debbie’s hobbies.

Ashley Vaughan

Marketing Coordinator

Ashley Vaughan has over a decade of experience in graphic design including both print and digital. She has worked as an in-house designer specializing in marketing and sales collateral for numerous companies prior to joining Greenstone. Ashley has expertise with long-form design and brand management. Her creativity, excellent attention to detail and top-notch design skills can be found within all of Greenstone’s marketing materials.

Ashley received a Bachelor’s Degree in Graphic Design from Kendall College of Art & Design. Ashley grew up in Saginaw, Michigan and enjoys concerts, downhill skiing and spending time with her family.

Dionne Sterling-Grant

Administrative Support

Dionne Sterling-Grant is the glue that binds the entire Greenstone family. She assists and supports all of the company’s business lines. Dionne is a team player and exhibits pride and passion in all of her work. Prior to joining Greenstone, Dionne has held other administrative assistant positions at Societe Generale, Fimat USA and BCD Travel.

Dionne grew up in Ocho Rios, Jamaica and enjoys spending time with her husband, two sons, as well as watching basketball and reading.

Georgia Diamantakos


Georgia Diamantakos oversees the accounts payable and accounts receivable department for Greenstone Asset Management. Her expertise in accounting spans several decades across various industries. Georgia is a native of Chicago, Illinois. She is an active cyclist and enjoys yoga.