Matthew James Costinett, beloved son, brother, dear friend to many, and a shrewd and meticulous jurist, passed away suddenly on July 21, 2022, far too young. Matt was born in Maryland on May 25, 1971 to Paul Robin Costinett and Jan Rey Granados Costinett. Matt is survived by his mother Jan, and brothers Paul and Chris.
Matt grew up exploring the great outdoors of southern Maryland, where his love of rocks, minerals, and the natural sciences was born. Matt went on to earn a Bachelor of Science in geology at the University of Maryland, College Park. After college, he worked as an environmental and energy consultant in Arlington, VA. In his spare time, he enjoyed hiking and going for long bike rides and runs, and even ran (and finished) the Marine Corps Marathon. A voracious learner always yearning for more, he decided to pursue a career in environmental law and moved to Denver, earning his law degree at the University of Denver, Sturm College of Law in 2003.
As a practicing attorney, Matt developed a diverse legal practice, but he became heralded within Denver legal circles as an artful lawyer with unparalleled knowledge of oil and gas law, his fastidiously drafted title opinions, and for his strong client advocacy skills. Matt was always generous about sharing his time and knowledge with others, and he trained and mentored a fair number of younger attorneys starting out in their careers. Matt ultimately transitioned his practice to renewable energies working at the Polsinelli law firm. Matt was kind, fiercely loyal to those whom he loved, always dependable, and selflessly thoughtful of others. He had a clever and witty sense of humor, he loved animals (particularly cats) and his kindness, generosity, and intellectual curiosity will be missed terribly, as will his home-grown pumpkins and annual Christmas cards. Most of all, Matt will be missed by those who loved him dearly and who will always cherish his memory as a blessing.
In lieu of flowers, please consider a donation in honor of Matt’s memory to the American Foundation for Suicide Prevention. A memorial fund has been established in his name at